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#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
using namespace std;

// Zlozonosc: 
// preprocessing O(n)
// zapytania	 O(qlogn)

long long potegi[200009], newton[200009][3], n, q;
long long r, g, b, diff1, diff2;
const long long M = 1e9 + 7;
string s;

long long fastpow(long long a, long long p)
{
	if(p == 0) return 1;
	if(p == 1) return a;
	if(p % 2 == 0)
	{
		long long b = fastpow(a, p/2);
		return ((b * b) % M);
	}
	long long b = fastpow(a, p-1);
	return ((a * b) % M);
}

void prep()
{
	potegi[0] = 1;
	for(int i=1; i<=n; i++) potegi[i] = (2 * potegi[i-1]) % M;
	newton[0][0] = 1;
	for(int i=1; i<=n; i++)
	{
		newton[i][0] = (newton[i-1][0] + newton[i-1][2]) % M;
		newton[i][1] = (newton[i-1][0] + newton[i-1][1]) % M;
		newton[i][2] = (newton[i-1][1] + newton[i-1][2]) % M;
	}
	
	for(int i=0; i<s.size(); i++)
	{
		if(s[i] == 'C') r++;
		else if(s[i] == 'Z') g++;
		else b++;	
	}
	for(int i=0; i<s.size(); i++) if((i % 2 == 0 && s[i] == 'C') || (i % 2 == 1 && s[i] == 'Z')) diff1++;
	for(int i=0; i<s.size(); i++) if((i % 2 == 0 && s[i] == 'Z') || (i % 2 == 1 && s[i] == 'C')) diff2++;
	return;
}

void solve()
{
	long long d, wyn;
	d = (n - 2 * r) % 3;
	if(d < 0) d += 3;
	if(d != 0) d = 3 - d;			// 2 * x = n - 2 * r (mod 3)
	wyn = newton[b][d];
	
	if(n % 2 == 1)
	{
		if(diff1 == 0) wyn++;
		if(diff2 == 0) wyn++; 
		wyn %= M;
	}
	
	wyn = (potegi[b] - wyn) % M;
	if(wyn < 0) wyn += M;
	cout<<wyn<<"\n";
	return;
}

void upd()
{
	int a;
	char c;
	cin>>a>>c;
	if(s[a-1] == 'C')
	{
		r--;
		if((a-1) % 2 == 0) diff1--;
		else diff2--;
	}
	else if(s[a-1] == 'Z')
	{
		g--;
		if((a-1) % 2 == 0) diff2--;
		else diff1--;
	}
	else b--;
	if(c == 'C')
	{
		r++;
		if((a-1) % 2 == 0) diff1++;
		else diff2++;
	}
	else if(c == 'Z')
	{
		g++;
		if((a-1) % 2 == 0) diff2++;
		else diff1++;
	}
	else b++;
	s[a-1] = c;
	return;
}

int main()
{
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin>>n>>q>>s;
	r = g = b = 0;
	diff1 = diff2 = 0;
	prep();
	solve();
	for(int i=1; i<=q; i++)
	{
		upd();
		solve();
	}
	return 0;
}