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#include <bits/stdc++.h>
using namespace std;

const int N = 200100;
const long long mod = 1e9+7;

int a[N];

struct node {
    long long dp[2][2];
    long long dpSingle[2];
    long long dpDouble[2];
    long long dpTriple[2];
    long long dpAnd[2];
};

node t[N*4];

/*
lU
lR
lG

rU
rR
rG



merge rules:

odd_x + odd_x -> ~x
odd_x + even_x -> x
even_x + odd_~x -> ~x

even_x + even_~x -> x and ~x

odd_x + odd~x -> even_~x
odd_x + even~x -> odd_x

even_x + odd~x -> odd_x
even_x + even_x -> even_x


dpSingle[2];
dpDouble[2];
dpTriple[2];
dpAnd[2];
dpDoubleAnd[2];

*/

node merge(node l, node r) {
    node ret;
    for (int i = 0; i < 2; i++)
        ret.dpSingle[i] = ret.dpDouble[i] = ret.dpTriple[i] = ret.dpAnd[i] = ret.dp[i][0] = ret.dp[i][1] = 0;

    ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[0] * r.dpSingle[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpSingle[0] * r.dpDouble[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[0] * r.dpTriple[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[0] * r.dpAnd[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[0] * r.dp[0][1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[0] * r.dp[0][0]) % mod;
ret.dpAnd[0] = (ret.dpAnd[0] + l.dpSingle[0] * r.dpSingle[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[0] * r.dpDouble[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[0] * r.dpTriple[1]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dpSingle[0] * r.dpAnd[1]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dpSingle[0] * r.dp[1][1]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dpSingle[0] * r.dp[1][0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpDouble[0] * r.dpSingle[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[0] * r.dpDouble[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dpTriple[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dpAnd[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpDouble[0] * r.dp[0][1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dp[0][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[0] * r.dpSingle[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpDouble[0] * r.dpDouble[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dpTriple[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dpAnd[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[0] * r.dp[1][1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[0] * r.dp[1][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[0] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[0] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[0] * r.dpTriple[0]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[0] * r.dpAnd[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[0] * r.dp[0][1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[0] * r.dp[0][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[0] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[0] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[0] * r.dpTriple[1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[0] * r.dpAnd[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[0] * r.dp[1][1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[0] * r.dp[1][0]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dpAnd[0] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpAnd[0] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpAnd[0] * r.dpTriple[0]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dpAnd[0] * r.dpAnd[0]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dpAnd[0] * r.dp[0][1]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dpAnd[0] * r.dp[0][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpAnd[0] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpAnd[0] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpAnd[0] * r.dpTriple[1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpAnd[0] * r.dpAnd[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpAnd[0] * r.dp[1][1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpAnd[0] * r.dp[1][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][1] * r.dpSingle[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dp[0][1] * r.dpDouble[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[0][1] * r.dpTriple[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[0][1] * r.dpAnd[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][1] * r.dp[0][1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[0][1] * r.dp[0][0]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dp[0][1] * r.dpSingle[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][1] * r.dpDouble[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[0][1] * r.dpTriple[1]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dp[0][1] * r.dpAnd[1]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dp[0][1] * r.dp[1][1]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dp[0][1] * r.dp[1][0]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dp[0][0] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][0] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dp[0][0] * r.dpTriple[0]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dp[0][0] * r.dpAnd[0]) % mod;
ret.dp[0][1] = (ret.dp[0][1] + l.dp[0][0] * r.dp[0][1]) % mod;
ret.dp[0][0] = (ret.dp[0][0] + l.dp[0][0] * r.dp[0][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][0] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[0][0] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dp[0][0] * r.dpTriple[1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dp[0][0] * r.dpAnd[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[0][0] * r.dp[1][1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dp[0][0] * r.dp[1][0]) % mod;
ret.dpAnd[1] = (ret.dpAnd[1] + l.dpSingle[1] * r.dpSingle[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[1] * r.dpDouble[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[1] * r.dpTriple[0]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dpSingle[1] * r.dpAnd[0]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dpSingle[1] * r.dp[0][1]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dpSingle[1] * r.dp[0][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[1] * r.dpSingle[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpSingle[1] * r.dpDouble[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[1] * r.dpTriple[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[1] * r.dpAnd[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpSingle[1] * r.dp[1][1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpSingle[1] * r.dp[1][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[1] * r.dpSingle[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpDouble[1] * r.dpDouble[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dpTriple[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dpAnd[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[1] * r.dp[0][1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dp[0][0]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpDouble[1] * r.dpSingle[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpDouble[1] * r.dpDouble[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dpTriple[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dpAnd[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpDouble[1] * r.dp[1][1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpDouble[1] * r.dp[1][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[1] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[1] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[1] * r.dpTriple[0]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[1] * r.dpAnd[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[1] * r.dp[0][1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[1] * r.dp[0][0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[1] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpTriple[1] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpTriple[1] * r.dpTriple[1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[1] * r.dpAnd[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpTriple[1] * r.dp[1][1]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpTriple[1] * r.dp[1][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpAnd[1] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dpAnd[1] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dpAnd[1] * r.dpTriple[0]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpAnd[1] * r.dpAnd[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpAnd[1] * r.dp[0][1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpAnd[1] * r.dp[0][0]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dpAnd[1] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dpAnd[1] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dpAnd[1] * r.dpTriple[1]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dpAnd[1] * r.dpAnd[1]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dpAnd[1] * r.dp[1][1]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dpAnd[1] * r.dp[1][0]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dp[1][1] * r.dpSingle[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][1] * r.dpDouble[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[1][1] * r.dpTriple[0]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dp[1][1] * r.dpAnd[0]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dp[1][1] * r.dp[0][1]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dp[1][1] * r.dp[0][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][1] * r.dpSingle[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dp[1][1] * r.dpDouble[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[1][1] * r.dpTriple[1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[1][1] * r.dpAnd[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][1] * r.dp[1][1]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[1][1] * r.dp[1][0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][0] * r.dpSingle[0]) % mod;
ret.dpDouble[0] = (ret.dpDouble[0] + l.dp[1][0] * r.dpDouble[0]) % mod;
ret.dpTriple[0] = (ret.dpTriple[0] + l.dp[1][0] * r.dpTriple[0]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dp[1][0] * r.dpAnd[0]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][0] * r.dp[0][1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dp[1][0] * r.dp[0][0]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dp[1][0] * r.dpSingle[1]) % mod;
ret.dpDouble[1] = (ret.dpDouble[1] + l.dp[1][0] * r.dpDouble[1]) % mod;
ret.dpTriple[1] = (ret.dpTriple[1] + l.dp[1][0] * r.dpTriple[1]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dp[1][0] * r.dpAnd[1]) % mod;
ret.dp[1][1] = (ret.dp[1][1] + l.dp[1][0] * r.dp[1][1]) % mod;
ret.dp[1][0] = (ret.dp[1][0] + l.dp[1][0] * r.dp[1][0]) % mod;


    return ret;
}

void build(int v, int l, int r) {
    if (l == r) {
        t[v].dpSingle[0] = t[v].dpSingle[1] = 0;
        if (a[l] == 2)
            t[v].dpSingle[0] = t[v].dpSingle[1] = 1;
        else
            t[v].dpSingle[a[l]] = 1;
        return;
    }
    int mid = (l+r)>>1;
    build(v+v, l, mid);
    build(v+v+1, mid+1, r);
    t[v] = merge(t[v+v], t[v+v+1]);
}

void update(int v, int l, int r, int pos, int x) {
    if (l == r) {
        t[v].dpSingle[0] = t[v].dpSingle[1] = 0;
        if (x == 2)
            t[v].dpSingle[0] = t[v].dpSingle[1] = 1;
        else
            t[v].dpSingle[x] = 1;
        return;
    }
    int mid = (l+r)>>1;
    if (pos <= mid)
        update(v+v, l, mid, pos, x);
    else
        update(v+v+1, mid+1, r, pos, x);
    t[v] = merge(t[v+v], t[v+v+1]);
}

long long get_ans() {
    long long ans = (t[1].dpSingle[0] + t[1].dpSingle[1]) % mod;
    ans = (ans + t[1].dpDouble[0] + t[1].dpDouble[1]) % mod;
    return ans;
}

void solve() {

    int n, tt;
    cin >> n >> tt;
    for (int i = 0; i < n; i++) {
        char c;
        cin >> c;
        if (c == 'Z')
            a[i] = 0;
        else if (c == 'C')
            a[i] = 1;
        else a[i] = 2;
    }
    build(1, 0, n-1);
    cout << get_ans() << "\n";
    while(tt--) {
        int pos;
        char c;
        cin >> pos >> c;
        --pos;
        int x;
        if (c == 'Z')
            x = 0;
        else if (c == 'C')
            x = 1;
        else x = 2;
        update(1, 0, n-1, pos, x);
        cout << get_ans() << "\n";
    }

    
}

int main(){

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t;
    t = 1;

    #ifdef Local
        // freopen("input.txt", "r", stdin);
        // freopen("output.txt", "w", stdout);
        // cin >> t;
    #endif
    // cin >> t;
    
    while(t--){
        solve();
    }


    return 0;
}