#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false), cin.tie(nullptr);
int n; string s;
cin >> n >> s;
struct Node {
int ans, sum, pre, suf;
Node operator+ (Node other) {
other.ans = min({ans + other.sum, sum + other.ans, pre + other.suf});
other.pre = min(pre, sum + other.pre);
other.suf = min(suf + other.sum, other.suf);
other.sum = sum + other.sum;
return other;
}
};
int tree_size = 1;
while (tree_size < n)
tree_size <<= 1;
vector<Node> tree(tree_size << 1);
for (int i = 0; i < n; i++) {
if (s[i] == 'C')
tree[i + tree_size] = Node{0, +1, 0, 0};
else
if (s[i] == 'T')
tree[i + tree_size] = Node{-1, -1, -1, -1};
}
for (int i = tree_size - 1; i; i--)
tree[i] = tree[i << 1 | 0] + tree[i << 1 | 1];
int q; cin >> q;
while (q--) {
int l, r; cin >> l >> r;
Node L{0, 0, 0, 0}, R{0, 0, 0, 0};
for (l += tree_size - 1, r += tree_size; l < r; l >>= 1, r >>= 1) {
if (l & 1)
L = L + tree[l++];
if (r & 1)
R = tree[--r] + R;
}
cout << - (L + R).ans << '\n';
}
}
