#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const int N=5e5+13;
int n, q;
int a[N];
struct Node {
int pre, suf, sum, res;
Node operator+(const Node& other) const {
return {
max(pre, sum + other.pre),
max(other.suf, other.sum + suf),
sum + other.sum,
max({res + other.sum, sum + other.res, pre + other.suf})
};
}
};
Node st[N * 4];
void build(int id, int l, int r) {
if (l == r) {
st[id] = {
max(0, a[l]),
max(0, a[l]),
a[l],
(a[l] == 1 ? 1 : 0)
};
return;
}
int mid = (l + r) / 2;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
st[id] = st[id * 2] + st[id * 2 + 1];
}
Node query(int id, int l, int r, int u, int v) {
if (r < u || l > v) return {0, 0, 0, 0};
if (u <= l && r <= v) return st[id];
int mid = (l + r) / 2;
return query(id * 2, l, mid, u, v) + query(id * 2 + 1, mid + 1, r, u, v);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
for (int i = 1; i <= n; i++) {
char c;
cin >> c;
a[i] = (c == 'T' ? 1 : -1);
}
build(1, 1, n);
cin >> q;
while (q--) {
int l, r;
cin >> l >> r;
cout << query(1, 1, n, l, r).res << '\n';
}
return 0;
}
