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// clang-format off
#include <bits/stdc++.h>

using namespace std;

#define ALL(x) (x).begin(), (x).end()

template<class C> void mini(C &a5, C b5) { a5 = min(a5, b5); }
template<class C> void maxi(C &a5, C b5) { a5 = max(a5, b5); }

#ifdef LOCAL
const bool debug = true;
#else
const bool debug = false;
#define cerr if (true) {} else cout
#endif
// clang-format on

#define int long long
#define double long double

const int INF = 1e18;
const int mod = 1e9 + 7;
const int nax = 1e6 + 100;

char arr[nax];
int counts[nax];
int counts2[2][nax];
int fib[nax][3];
int cur_pot = 1;

int N, Q;

int pot(int n, int k=mod-2) {
	int res = 1;
	while (k) {
		if (k % 2) {
			res = (res * n) % mod;
		}
		k /= 2;
		n = (n * n) % mod;
	}
	return res;
}

int solve() {
	int res = 0;
	int c = counts[(int)'C'];
	int z = counts[(int)'Z'];
	const int b = counts[(int)'N'];
	//int bb = b;
	
	if (c < z) {
		swap(c, z);
	}
	
	cerr << " " << c << " " << b << " " << z << " ";
	
	// różnica podzielna przez 3
	int diff = c + b - z;
	res += fib[b][(3-diff%3)%3];
	cerr << "  /3:" << res << " " << b << "  " << (3-diff)%3 << " ";
	/*while (diff % 3) {
		diff++;
		bb--;
	}
	if (bb >= 0) {
		res += bb / 3; // tu jakieś dwumiany jeszcze trzeba
	}*/
	
	// naprzemienne kolory
	if (N % 2 && N > 1) {
		if (counts2[0][(int)'C'] == 0 && counts2[1][(int)'Z'] == 0) {
			res++;
			cerr << "k1:" << res << " ";
		}
		if (counts2[1][(int)'C'] == 0 && counts2[0][(int)'Z'] == 0) {
			res++;
			cerr << "k2:" << res << " ";
		}
	}

	cerr << "\n";
	return (cur_pot + mod + mod - res) % mod;
}

void init() {
	fib[0][0] = 1;
	for (int i = 1; i < N + 10; i++) {
		for (int j = 0; j < 3; j++) {
			fib[i][j] = (fib[i-1][j] + fib[i-1][(j + 2) % 3]) % mod;
		}
	}
	for (int i = 0; i < 100; i++) {
		cerr << i << ": ";
		for (int j = 0; j < 3; j++) {
			cerr << fib[i][j] << " ";
		}
		cerr << "\n";
	}
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

	//cerr << (int)'Z' << " " << (int)'C' << " " << (int)'N' << "\n";
	//return 0; 
	int odw2 = pot(2);


	cin >> N >> Q;
	for (int i = 1; i <= N; i++) {
		cin >> arr[i];
		counts[(int)arr[i]]++;
		counts2[i % 2][(int)arr[i]]++;
		if (arr[i] == 'N') {
			cur_pot = (cur_pot * 2) % mod;
		}
	}
	init();
	
	cout << solve() << "\n";
	while (Q--) {
		int pos;
		char c;
		cin >> pos >> c;
		counts[(int)arr[pos]]--;
		counts2[pos % 2][(int)arr[pos]]--;
		if (arr[pos] == 'N') {
			cur_pot = (cur_pot * odw2) % mod;
		}
		arr[pos] = c;
		counts[(int)arr[pos]]++;
		counts2[pos % 2][(int)arr[pos]]++;
		if (c == 'N') {
			cur_pot = (cur_pot * 2) % mod;
		}
		cout << solve() << "\n";
	}

    return 0;
}/*
5 3
NNCCZ
3 N
2 Z
1 Z

3
5
3
1

1 3
N
1 Z
1 C
1 N
* 
4 1
NNNN
1 N
*/