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#pragma GCC optimize ("Ofast")
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define FOR(i, a, b) for (auto i=(a); i<(b); i++)
#define FORD(i, a, b) for (BigNum i=(a); i>(b); i--)
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define PPC(x) __builtin_popcountll(x)
#define MSB(x) (63 - __builtin_clzll(x))
#define LSB(x) __builtin_ctzll(x)
#define ARG(x, i) (get<i>(x))
#define ithBit(m, i) ((m) >> (i) & 1)
#define pb push_back
#define ft first
#define sd second
#define kw(a) ((a) * (a))
#ifdef DEBUG
#include "debug.h"
#else
#define dbg(...) 0
#endif
using namespace std; 

template <typename T1, typename T2> inline void remin(T1& a, T2 b) { a = min(a, (T1)b);	}
template <typename T1, typename T2> inline void remax(T1& a, T2 b) { a = max(a, (T1)b);	}

const int maxN = 1 << 18, mod = 1'000'000'007;

char T[maxN];
int n;

struct StuckChecker
{
	char banned[maxN];
	int collisions = 0;
	
	void init(char c)
	{
		char xr = 'C' ^ 'Z';
		FOR(i, 0, n)
		{
			banned[i] = c;
			if (c == T[i])
				collisions++;
			c ^= xr;
		}
	}
	
	void updt(int i, char c)
	{
		if (T[i] != banned[i] and c == banned[i])
			collisions++;
		if (T[i] == banned[i] and c != banned[i])
			collisions--;
	}
	
	bool stuckPossible()
	{	return n % 2 == 1 and collisions == 0;	}
} S[2];

long long dp[maxN][3];

void calcDp()
{
	dp[0][0] = 1;
	dp[1][0] = dp[1][1] = 1;
	
	FOR(i, 2, n+1) FOR(j, 0, 3)
		dp[i][j] = (dp[i-1][j] + dp[i-1][(j+2) % 3]) % mod;
	
	long long pow2 = 1ll;
	FOR(i, 0, n+1)
	{
		assert((dp[i][0] + dp[i][1] + dp[i][2]) % mod == pow2);
		pow2 = pow2 * 2 % mod;
	}
}

long long query(int& r, int& g, int& b)
{
	long long ret = 0;
	
	FOR(s, 0, min(b+1,3))
		if ((r + s) % 3 != (g + b-s) % 3)
			ret += dp[b][s];
			
	FOR(s, 0, 2)
		if (S[s].stuckPossible())
			ret += mod-1;
			
	return ret % mod;
}

void solve()
{
	int q;
	scanf ("%d%d%s", &n, &q, T);
	
	S[0].init('C'), S[1].init('Z');
	calcDp();
	map <char, int> M;
	for (char c : "CZN")
		M[c] = std::count(T, T+n, c);
	int& r = M['C'];
	int& g = M['Z'];
	int& b = M['N'];
	
	printf("%lld\n", query(r, g, b));
	
	while (q--)
	{
		int i;
		char buff[42];
		scanf("%d%s", &i, buff);
		char c = buff[0];
		i--;

		FOR(s, 0, 2)
			S[s].updt(i, c);

		M[T[i]]--;
		T[i] = c;
		M[T[i]]++;

		printf("%lld\n", query(r, g, b));
	}
}
 
int main()
{
	int t = 1;
	//scanf ("%d", &t);
	FOR(tid, 1, t+1)
	{
		//printf("Case #%d: ", tid);
		solve();
	}
	return 0;
}