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// Olaf Surgut 12.12.2022 18:48:09
#include <bits/stdc++.h>

using namespace std;

const int N = 200000 + 11;

const int mod = 1e9 + 7;

int n, q;
char s[N];
int cnt[3][2], ile[N][3], pot[N];

int main() {
	scanf("%d%d", &n, &q);
	scanf("%s", s + 1);
	
	auto typ = [&](char c) {
		if (c == 'C')	return 0;
		else
		if (c == 'Z')	return 1;
		else
		if (c == 'N')	return 2;
		return -1;
	};

	for (int i = 1; i <= n; i++) {
		cnt[typ(s[i])][i % 2]++;
	}

	ile[0][0] = 1;
	pot[0] = 1;
	for (int i = 1; i <= n; i++) {
		(ile[i][0] = ile[i - 1][2] + ile[i - 1][1]) %= mod;
		(ile[i][1] = ile[i - 1][0] + ile[i - 1][2]) %= mod;
		(ile[i][2] = ile[i - 1][1] + ile[i - 1][0]) %= mod;
		(pot[i] = pot[i - 1] * 2) %= mod;
	}

	auto solve = [&]() {
		int ans = pot[cnt[2][0] + cnt[2][1]];
		if (cnt[0][0] == 0 && cnt[1][1] == 0) {
			(ans += mod - 1) %= mod;
		}

		if (cnt[0][1] == 0 && cnt[1][0] == 0) {
			(ans += mod - 1) %= mod;
		}
		
		int r = cnt[0][0] + cnt[0][1] - cnt[1][0] - cnt[1][1];
		r = ((r % 3) + 3) % 3;

		(ans += mod - ile[cnt[2][0] + cnt[2][1]][r]) %= mod;
	
		return ans;
	};

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

	while (q--) {
		int p; char c; cin >> p >> c;

		cnt[typ(s[p])][p % 2]--;
		s[p] = c;
		cnt[typ(s[p])][p % 2]++;

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