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#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <ranges>
#include <set>
#include <string>
#include <vector>

using namespace std;

const int MOD = 1e9 + 7;

template <int M>
struct modint {
    int v;
    modint(int xx = 0) : v(xx % M) { v += (M & (0 - (v < 0))); }

    friend istream& operator>>(istream& i, modint& n) { return i >> n.v; }
    friend ostream& operator<<(ostream& o, const modint n) { return o << n.v; }

    modint& operator+=(const modint n) {
        v += n.v;
        v -= (M & (0 - (v >= M)));
        return *this;
    }
    modint& operator-=(const modint n) {
        v -= n.v;
        v += (M & (0 - (v < 0)));
        return *this;
    }
    friend modint operator+(const modint n, const modint m) {
        return modint(n) += m;
    }
    friend modint operator-(const modint n, const modint m) {
        return modint(n) -= m;
    }
};

using modi = modint<MOD>;

vector<vector<int>> memo;

modi f3(int n, int parity) {
    parity = ((parity % 3) + 3) % 3;
    if (n == 0) return parity == 0;
    if (memo[n][parity] != -1) return memo[n][parity];
    modi res = f3(n - 1, parity) + f3(n - 1, parity - 1);
    return memo[n][parity] = res.v;
}

int n;

modi f2(int x, int y) {
    int z = n - (x + y);
    modi res = 0;
    for (int d = 0; d < 3; d++) {
        if ((x + d + 2 * (y + z - d) + 2) % 3 != 0) continue;
        res += f3(z, d);
    }
    return res;
}

int q;
string s;
int x, y;

vector<int> broken(2);
bool can_break;

modi f() {
    int d = 0;
    d += can_break && (broken[0] == n);
    d += can_break && (broken[1] == n);

    return f2(x, y) + f2(y, x) - d;
}

void update(int i, bool added) {
    char c = s[i];
    int d = added ? 1 : -1;
    if (c == 'C') {
        x += d;
        broken[(i + 1) % 2] += d;
    } else if (c == 'Z') {
        y += d;
        broken[i % 2] += d;
    } else {
        assert(c == 'N');
        for (auto& p : broken) p += d;
    }
}

void solve() {
    cin >> n >> q;
    cin >> s;
    assert(s.size() == n);

    int a = ((n + 1) / 2);
    int b = n - a;

    can_break = n > 1 && ((a + 2 * b) % 3 == 1);

    memo.resize(n + 1);
    for (auto& u : memo) {
        u.resize(3);
        for (auto& v : u) v = -1;
    }

    for (int i = 0; i < n; i++) update(i, true);

    cout << f() << "\n";
    while (q--) {
        int k;
        string c;
        cin >> k >> c;
        k--;
        assert(c.size() == 1);
        update(k, false);
        s[k] = c[0];
        update(k, true);
        cout << f() << "\n";
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.exceptions(cin.failbit);
    cin.tie(0);
    solve();
}