#include <bits/stdc++.h>
#define int long long
#define MAX 600000
using namespace std;
typedef array<int, 4> tp; // sm, lmax, rmax, mx;
tp merge(tp X, tp Y) {
tp res = {X[0] + Y[0], X[1], Y[2], 0};
bool fX = false, fY = false;
if (X[0] + Y[1] >= X[1])
fX = true, res[1] = X[0] + Y[1];
if (X[2] + Y[0] >= Y[2])
fY = true, res[2] = X[2] + Y[0];
if (fX && fY)
res[3] = X[2] + Y[1];
return res;
}
int A[MAX];
tp tree[MAX * 4];
void init(int n, int s, int e) {
if (s == e)
tree[n] = {A[s], A[s], A[s], A[s]};
else {
int m = s + e >> 1;
init(n << 1, s, m), init(n << 1 | 1, m + 1, e);
tree[n] = merge(tree[n << 1], tree[n << 1 | 1]);
}
}
tp query(int n, int s, int e, int l, int r) {
if (r < s || e < l)
return {0, 0, 0, 0};
else if (l <= s && e <= r)
return tree[n];
else {
int m = s + e >> 1;
return merge(
query(n << 1, s, m, l, r),
query(n << 1 | 1, m + 1, e, l, r));
}
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int N, Q, L, R, ans;
tp res;
string S;
cin >> N >> S;
for (int i = 1; i <= N; i++)
A[i] = S[i - 1] == 'T' ? 1 : -1;
init(1, 1, N);
cin >> Q;
while (Q--) {
cin >> L >> R;
res = query(1, 1, N, L, R);
ans = max(0ll, res[1]) + max(0ll, res[2]);
if (res[3] != 0)
ans = max({0ll, res[1], res[2]});
cout << ans << '\n';
}
return 0;
}
