#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;
struct Node {
int l_max, r_max, tot, ans;
Node operator+(Node b) {
Node ret;
ret.l_max = max(l_max, b.l_max + tot);
ret.r_max = max(r_max + b.tot, b.r_max);
ret.tot = tot + b.tot;
ret.ans = max(max(ans + b.tot, b.ans + tot), l_max + b.r_max);
return ret;
}
};
Node segtree[2000001];
char s[500001];
int n;
void build(int node = 1, int l = 1, int r = n) {
if (l == r) {
if (s[l] == 'T') segtree[node] = {1, 1, 1, 1};
else segtree[node] = {0, 0, -1, 0};
} else {
int mid = (l + r) / 2;
build(node * 2, l, mid);
build(node * 2 + 1, mid + 1, r);
segtree[node] = segtree[node * 2] + segtree[node * 2 + 1];
}
}
Node query(int a, int b, int node = 1, int l = 1, int r = n) {
if (l > b || r < a) return {0, 0, 0, 0};
if (l >= a && r <= b) return segtree[node];
int mid = (l + r) / 2;
return query(a, b, node * 2, l, mid) +
query(a, b, node * 2 + 1, mid + 1, r);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n;
FOR(i, 1, n + 1) cin >> s[i];
build();
int q;
cin >> q;
while (q--) {
int a, b;
cin >> a >> b;
cout << query(a, b).ans << '\n';
}
return 0;
}
