#include <bits/stdc++.h>
#include <ios>
#include <iostream>
#include <random>
using namespace std;
using ll = long long;
using P = pair<int, int>;
#define f first
#define s second
const int MOD = 1e9+7;
const ll inf = 4*1e18;
const int mx = 5*1e5+5;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
struct Node {
int l, r, s, a;
Node operator+(Node b) {
Node ret;
ret.l = max(l, s+b.l);
ret.r = max(r+b.s, b.r);
ret.s = s + b.s;
ret.a = max({a+b.s, s+b.a, l+b.r});
return ret;
}
};
Node segtree[2000001];
char s[500001];
int n;
void build(int v, int l, int r) {
if (l == r) {
if (s[l-1] == 'T') {
segtree[v] = {1, 1, 1, 1};
} else {
segtree[v] = {0, 0, -1, 0};
}
return;
}
int mid = (l+r)/2;
build(2*v, l, mid);
build(2*v+1, mid+1, r);
segtree[v] = segtree[2*v] + segtree[2*v+1];
}
Node query(int v, int l, int r, int ql, int qr) {
if (qr < l || ql > r) {return {0, 0, 0, 0};}
if (ql >= l && qr <= r) return segtree[v];
int mid = (ql+qr)/2;
Node x = query(2*v, l, r, ql, mid)+query(2*v+1, l, r, mid+1, qr);
return x;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
cin >> n;
for (int i = 0; i < n; i++) {
cin >> s[i];
}
build(1, 1, n);
int q; cin >> q;
while (q--) {
int a, b; cin >> a >> b;
cout << query(1, a, b, 1, n).a << "\n";
}
}
