#include <bits/stdc++.h>
using namespace std;
constexpr int N = 5e5 + 5;
int n, Q;
char s[N];
struct info {
int ans, sum, pre, suf;
} tr[N << 2];
info pushup(info l, info r) {
info u;
u.ans = max({l.pre + r.suf, l.sum + r.ans, r.sum + l.ans});
u.sum = l.sum + r.sum;
u.pre = max(l.pre, l.sum + r.pre);
u.suf = max(r.suf, r.sum + l.suf);
return u;
}
void build(int u = 1, int l = 1, int r = n) {
if (l == r) {
tr[u].sum = s[l];
tr[u].ans = tr[u].pre = tr[u].suf = max<int>(s[l], 0);
return;
}
int mid = (l + r) / 2;
build(u * 2, l, mid), build(u * 2 + 1, mid + 1, r);
tr[u] = pushup(tr[u * 2], tr[u * 2 + 1]);
}
info query(int ql, int qr, int u = 1, int l = 1, int r = n) {
if (l >= ql && r <= qr) {
return tr[u];
}
int mid = (l + r) / 2;
if (ql > mid) return query(ql, qr, u * 2 + 1, mid + 1, r);
if (qr <= mid) return query(ql, qr, u * 2, l, mid);
return pushup(query(ql, qr, u * 2, l, mid), query(ql, qr, u * 2 + 1, mid + 1, r));
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> s[i];
s[i] = (s[i] == 'T' ? 1 : -1);
}
build();
cin >> Q;
while (Q--) {
int l, r;
cin >> l >> r;
cout << query(l, r).ans << "\n";
}
return 0;
}
