#include <bits/stdc++.h>
using namespace std;
 
int main(){
	int N;
	cin >> N;
	string s;
	cin >> s;
	if(N == 1){
		cout << 1 << '\n';
		exit(0);
	}
	vector<int> a(N);
	for(int i = 0;i < N;i++){
		if(s[i] == 'F'){
			a[i] = 0;
		}else if(s[i] == 'G'){
			a[i] = 1;
		}else{
			a[i] = 2;
		}
	}
	int pref[3][N];
	for(int i = 0;i < 3;i++){
		for(int j = 0;j < N;j++){
			pref[i][j] = (j ? pref[i][j - 1] : 0) + (a[j] == i);
		}
	}
	int Q;
	cin >> Q;
	int x;
	cin >> x >> x;
	int ans = 0;
 
	for(int i = 0;i < N;i++){
		// Can this be good
			bool ok = true;
 
			int back_b =  (i ? pref[(a[i] - 1 + 3) % 3][i - 1] : 0);
			int back_g =  (i ? pref[(a[i] + 1) % 3][i - 1] : 0);
 
 
			int fr_b =  pref[(a[i] - 1 + 3) % 3][N - 1];
			int fr_g =  pref[(a[i] + 1) % 3][N - 1];
 
			fr_b -= back_b;
			fr_g -= back_g;
 
			if(back_b > 0 && back_g == 0) ok = false;
			if(fr_b > 0 && fr_g == 0) ok = false;
 
 
			if(ok) ans ++;
 
 
	}
 
	cout << ans << '\n';
 
	return 0;
}

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