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#include <bits/stdc++.h>
#ifdef LOC
#include "debuglib.h"
#else
#define deb(...)
#define DBP(...)
#endif
using namespace std;
using   ll         = long long;
using   vi         = vector<int>;
using   pii        = pair<int, int>;
#define pb           push_back
#define mp           make_pair
#define x            first
#define y            second
#define rep(i, b, e) for (int i = (b); i < (e); i++)
#define each(a, x)   for (auto& a : (x))
#define all(x)       (x).begin(), (x).end()
#define sz(x)        int((x).size())

constexpr int MOD = 1e9+7;

void run() {
	int n, q;
	string s;
	cin >> n >> q >> s;

	int cnt[3] = {};
	int aba = 0, bab = 0;

	vector<array<ll, 3>> changes(n+1);
	changes[0] = {1, 0, 0};
	rep(i, 1, sz(changes)) {
		rep(v, 0, 3) {
			changes[i][v] = (changes[i-1][(v+1)%3] + changes[i-1][(v+2)%3]) % MOD;
		}
	}

	auto get = [&](int i) {
		return s[i] == 'C' ? 0 : s[i] == 'Z' ? 1 : 2;
	};

	auto update = [&](int i, int sign) {
		int v = get(i);
		cnt[v] += sign;
		aba += (v == 2 || v == i%2) * sign;
		bab += (v == 2 || v != i%2) * sign;
	};

	auto answer = [&]() {
		int fixed = (cnt[0]-cnt[1]+n*3) % 3;
		ll ways = changes[cnt[2]][(4-fixed)%3];
		ways += changes[cnt[2]][(5-fixed)%3];
		if (n > 1 && n%2 == 1) {
			ways -= (aba == n);
			ways -= (bab == n);
		}
		ways %= MOD;
		if (ways < 0) ways += MOD;
		return ways;
	};

	rep(i, 0, n) {
		update(i, 1);
	}

	cout << answer() << '\n';

	while (q--) {
		int i;
		char c;
		cin >> i >> c;
		i--;
		update(i, -1);
		s[i] = c;
		update(i, 1);
		cout << answer() << '\n';
	}
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(10);
	run();
	cout << flush; _Exit(0);
}