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#include<cstdio>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<stack>

using namespace std;

typedef vector<int> VI;
typedef long long LL;
typedef vector<LL> VLL;
typedef pair<int, int> PII;

#define FOR(x, b, e) for(int x=b; x<=(e); ++x)
#define FORD(x, b, e) for(int x=b; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define VAR(v, n) __typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB push_back
#define ST first
#define ND second

LL p = 1e9 + 7;
int n, q;
string chain;
VLL factorial;

LL gcdw(LL a, LL b, LL &l, LL &k) {
    if(!a) {
        l = 0;
        k = 1;
        return b;
    }
    LL d = gcdw(b % a, a, k, l);
    l -= (b / a) * k;
    return d;
}

LL revMod(LL a, LL m) {
    LL x, y;
    if(gcdw(a, m, x, y) != 1) return -1;
    return (x % m + m) % m;
}

LL newton(int k, int nn) {
    return factorial[nn] * revMod(factorial[k] * factorial[nn - k] % p, p) % p;
}

int exclusions(VI &r, VI &g, int b) {
    if (n == 1) return 0;
    LL result = 0;
    int tr = r[0] + r[1];
    int tg = g[0] + g[1];
    if (n > 3 && n % 3 == 0) {
        if (tr == 0) result++;
        if (tg == 0) result++;
    }
    if (n % 2 == 0) {
        if (n / 2 - tr >= 0) result += newton(n / 2 - tr, b);
    } else {
        if (r[0] == 0 && g[1] == 0) result++;
        if (r[1] == 0 && g[0] == 0) result++;
        int x = (n / 2) - 1;
        if (x >= tr) result += newton(x - tr, b);
        if (x >= tg) result += newton(x - tg, b);
    }
    return result % p;
}

int main() {
	ios_base::sync_with_stdio(0);
    cin.tie(NULL); cout.tie(NULL);
    cin >> n >> q >> chain;
    VI ans(n + 1);
    factorial.resize(n + 1);
    LL tmp = 1;
    factorial[0] = 1;
    for (int i = 1; i <= n; i++) {
        tmp *= i;
        tmp %= p;
        factorial[i] = tmp;
    }
    tmp = 1;
    for (int i = 1; i <= n; i++) {
        tmp <<= 1;
        tmp %= p;
        ans[i] = tmp;
    }
    int blue = 0;
    VI green(2), red(2);
    REP(i, n) {
        if (chain[i] == 'C') red[i % 2]++;
        else if (chain[i] == 'Z') green[i % 2]++;
        else blue++;
    }
    cout << (p + ans[blue] - exclusions(red, green, blue)) % p << '\n';
    REP(i, q) {
        int k;
        string change;
        cin >> k >> change;
        k--;
        if (chain[k] == 'C') red[k % 2]--;
        else if (chain[k] == 'Z') green[k % 2]--;
        else blue--;
        chain[k] = change[0];
        if (chain[k] == 'C') red[k % 2]++;
        else if (chain[k] == 'Z') green[k % 2]++;
        else blue++;
        cout << (p + ans[blue] - exclusions(red, green, blue)) % p << '\n';
    }
    return 0;
}