#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define md ((l + r) >> 1)
const int N = 1'000'005;
int a[N];
struct node {
int s, prf, suf, ans;
node() {
s = prf = suf = ans = 0;
}
node(int x) {
s = x;
prf = suf = ans = max(x, 0);
}
friend node operator+(const node &l, const node &r) {
node ret;
ret.s = l.s + r.s;
ret.prf = max(l.prf, l.s + r.prf);
ret.suf = max(r.suf, l.suf + r.s);
ret.ans = max({l.ans + r.s, l.s + r.ans, l.prf + r.suf});
return ret;
}
} seg[1 << 21];
void build(int i, int l, int r) {
if (l == r) {
seg[i] = a[l];
return;
}
build(i << 1, l, md);
build(i << 1 | 1, md + 1, r);
seg[i] = seg[i << 1] + seg[i << 1 | 1];
}
node get(int i, int l, int r, int s, int e) {
if (s <= l && r <= e) {
return seg[i];
}
if (r < s || e < l) {
return node();
}
return get(i << 1, l, md, s, e) + get(i << 1 | 1, md + 1, r, s, e);
}
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
int n;
cin >> n;
for (int i = 0; i < n; i++) {
char c;
cin >> c;
a[i] = (c == 'T'? 1 : -1);
}
build(1, 0, n - 1);
int q;
cin >> q;
while (q--) {
int l, r;
cin >> l >> r;
l--, r--;
cout << get(1, 0, n - 1, l, r).ans << '\n';
}
return 0;
}
