#include <bits/stdc++.h>
using namespace std;
int main(){
int N;
cin >> N;
string s;
cin >> s;
if(N == 1){
cout << 1 << '\n';
}
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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