#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll, ll>
#define fi first
#define sec second
#define ld long double
const int MAXN = 2e3;
const ll INF = 4e18;
const int MOD = 1e9 + 7;
ll ps[MAXN + 5][2];
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int tc = 1;
// cin >> tc;
for(;tc--;){
ll N; cin >> N;
string S; cin >> S;
S = '%' + S;
for(int i = 1; i <= N; i++){
ps[i][0] = ps[i - 1][0] + (S[i] == 'C');
ps[i][1] = ps[i - 1][1] + (S[i] == 'T');
}
ll Q; cin >> Q;
for(int i = 1; i <= Q; i++){
ll l, r; cin >> l >> r;
ll lf = 1, rg = ps[r][1] - ps[l - 1][1], ans = 0;
for(;lf <= rg;){
ll mid = (lf + rg) / 2;
ll cnt = 0;
for(int j = l; j <= r; j++){
if(S[j] == 'T' && ps[j][0] - ps[l - 1][0] - (cnt + 1) >= 0 && ps[r][0] - ps[j - 1][0] - (mid - cnt) >= 0){
cnt++;
}
}
if(cnt >= mid){
ans = mid;
lf = mid + 1;
}
else rg = mid - 1;
}
cout << r - l + 1 - (ps[r][0] - ps[l - 1][0] + ans) << "\n";
}
}
}
/*
*/
