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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair <int, int> pii;
#define se second
#define fi first

const int N = 2e5;
const int mod = 1e9 + 7;

int n, q, c, z, k;
char a[N + 5];
ll pw[N + 5];
char y;
ll res;
bool t;
unordered_set <int> s;

ll Solve(bool t){
    if(n == 1){
        return (a[0] == 'N' ? 2 : 1);
    }
    if(!t and c + z == n){
        return 0;
    }
    int r = (c - z) % 3;
    if(c == 0 and z == 0){
        return ((pw[n - c - z + 1] + (n % 2 ? -2 : 2)) / 3 - !(n % 2)) % mod;
    }
    if(!r){
    //cout << "bla\n";
        return ((pw[n - c - z + 1] + ((n - c - z) % 2 ? 2 : -2)) / 3 - !t) % mod;
    }else{
        return (pw[n - c - z] - (pw[n - c - z] / 3 + (pw[n - c - z] % 3 == 1 ? 0 : 1))) % mod;
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin >> n >> q;
    pw[0] = 1ll;
    for(int i=1; i<=n+1; i++){
        pw[i] = 2ll * pw[i - 1];
        pw[i] %= mod;
    }

    cin >> a[0];
    c += (a[0] == 'C');
    z += (a[0] == 'Z');
    for(int i=1; i<n; i++){
        cin >> a[i];
        c += (a[i] == 'C');
        z += (a[i] == 'Z');
        if(a[i] != 'N' and a[i - 1] == a[i]){
            t = true;
            s.insert(i);
        }
    }
    cout << Solve(t) << "\n";
    while(q --){
        cin >> k >> y;
        k --;
        if(s.find(k + 1) != s.end()){
            s.erase(k + 1);

        }
        if(y != 'N'){
            if(k > 0 and a[k - 1] == y){
                s.insert((k));
            }
            if(k < n - 1 and a[k + 1] == y){
                s.insert(k + 1);
            }

        }
        t = (s.size() > 0);
        if(y == 'C'){
            c ++;
            z -= (a[k] == 'Z');
        }
        if(y == 'Z'){
            z ++;
            c -= (a[k] == 'C');
        }
        if(y == 'N'){
            c -= (a[k] == 'C');
            z -= (a[k] == 'Z');
        }
        a[k] = y;
        cout << Solve(t) << "\n";
    }
    return 0;
}