// Andrei-Costin Constantinescu
// O(N^2)
#include <bits/stdc++.h>
using namespace std;
const int NMAX = 500000 + 5;
int N, v[NMAX];
int main() {
//freopen("data.in", "r", stdin);
cin >> N;
assert(1 <= N && N <= 500000);
string votes;
cin >> votes;
assert(static_cast <int>(votes.size()) == N);
for (int i = 1; i <= N; ++ i) {
assert(votes[i - 1] == 'C' || votes[i - 1] == 'T');
v[i] = votes[i - 1] == 'C' ? 1 : -1;
}
int Q = 0;
cin >> Q;
assert(1 <= Q && Q <= 500000);
vector <int> marked;
for (int i = 1; i <= Q; ++ i) {
int l, r;
cin >> l >> r;
assert(1 <= l && l <= r && r <= N);
marked.clear();
int sum = 0, ans = 0;
for (int j = l; j <= r; ++ j) {
sum += v[j];
if (sum < 0)
sum = 0, ++ ans, marked.push_back(j);
}
sum = 0;
for (int j = r, k = marked.size() - 1; j >= l; -- j) {
while (k >= 0 && marked[k] > j)
-- k;
if (k >= 0 && marked[k] == j)
continue;
sum += v[j];
if (sum < 0)
sum = 0, ++ ans;
}
cout << ans << '\n';
}
return 0;
}
