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

#ifdef DEBUG
#include "debug.h"
#else
#define debug(...) ;
#endif

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)

#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repp(i, n, m) for (int i = (n); i < (m); ++i)

#define repr(i, n) for (int i = (n) - 1; i >= 0; --i)
#define reppr(i, n, m) for (int i = (m) - 1; i >= (n); --i)

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using pi = pair<int, int>;
using pll = pair<ll, ll>;

template <typename T, typename V> void mini(T& a, V b) {if (b < a) a = b; }
template <typename T, typename V> void maxi(T& a, V b) {if (b > a) a = b; }

const int MOD = 1e9 + 7;
struct modint {
    int x;

    modint operator+(modint o) {
        return {(x + o.x) % MOD};
    }

    modint operator*(modint o) {
        return {ll(x) * o.x % MOD};
    }
};

void __dbg(modint m) {
    cout << m.x;
}

using tab = array<modint, 3>;

tab comb(tab a, tab b) {
    return {
        a[0]*b[0] + a[1]*b[2] + a[2]*b[1],
        a[0]*b[1] + a[1]*b[0] + a[2]*b[2],
        a[0]*b[2] + a[1]*b[1] + a[2]*b[0]
    };
}

int mp(char ch) {
    if (ch == 'C')
        return 0;
    if (ch == 'Z')
        return 1;
    if (ch == 'N')
        return 2;
    assert(false);
}

void solve() {
    int n, q;
    cin >> n >> q;

    string s;
    cin >> s;

    int cnt[3] = {0, 0, 0};
    int badAlternating[2] = {0, 0};

    for (int i = 0; i < n; ++i) {
        int ch = mp(s[i]);

        ++cnt[ch];

        if (ch != 2)
            ++badAlternating[1&(ch^i)];
    }

    vector<vector<tab>> V;
    V.emplace_back(vector<tab>{tab{{modint{1}, modint{0}, modint{0}}}, tab{{modint{0}, modint{1}, modint{0}}}});
    V.emplace_back(vector<tab>{tab{{modint{1}, modint{0}, modint{0}}}, tab{{modint{0}, modint{0}, modint{1}}}});
    V.emplace_back(vector<tab>{tab{{modint{1}, modint{0}, modint{0}}}, tab{{modint{0}, modint{1}, modint{1}}}});

    for (auto& vec : V) {
        while (vec.size() <= n)
            vec.push_back(comb(vec[1], vec.back()));
    }

    auto calc = [&](){
        debug(cnt[0],cnt[1],cnt[2],badAlternating[0],badAlternating[1]);

        tab tot = comb(comb(V[0][cnt[0]], V[1][cnt[1]]), V[2][cnt[2]]);

        modint nonzero = tot[1] + tot[2];

        nonzero.x -= bool((n&1) && !badAlternating[0] && n>1);
        nonzero.x -= bool((n&1) && !badAlternating[1] && n>1);

        nonzero = nonzero + modint{MOD};
        return nonzero.x;
    };

    cout << calc() << '\n';
    while (q--) {
        int i;
        char ch;
        cin >> i >> ch;
        --i;

        if (mp(s[i]) != 2)
            --badAlternating[1&(mp(s[i])^i)];
        --cnt[mp(s[i])];

        s[i] = ch;

        if (mp(s[i]) != 2)
            ++badAlternating[1&(mp(s[i])^i)];
        ++cnt[mp(s[i])];

        cout << calc() << '\n';
    }
}

int main() {
#ifndef DEBUG
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
#endif
    int z = 1;
    // scanf("%d", &z);
    while (z--)
        solve();
    return 0;
}