#include <bits/stdc++.h>
#define pb push_back
#define all(v) v.begin(), v.end()
#define sz(x) (int)(x).size()
using namespace std;
using ll = long long;
using ld = long double;
const int N = 1e6 + 5;
const ll mod = 1e9 + 7;
const ld eps = 1e-6;
const ld Pi = acos(-1.0);
int n, q;
string s;
int used[N], timer;
void solve()
{
cin >> n >> s;
s = " " + s;
// for (int i = 1; i <= n; ++i)
// {
// pref[i] = pref[i - 1] + (s[i] == 'T');
// }
// for (int i = n + 1; i >= 1; --i)
// {
// suf[i] = suf[i + 1] + (s[i] == 'T');
// }
cin >> q;
for (int j = 1; j <= q; ++j)
{
int l, r;
cin >> l >> r;
int ans = 0, bal = 0;
++timer;
for (int i = l; i <= r; ++i)
{
if (s[i] == 'C')
++bal;
else
--bal;
if (bal < 0)
{
++ans;
++bal;
}
}
int cnt = 0;
for (int i = l; i <= r && cnt < ans; ++i)
{
if (s[i] == 'T')
{
++cnt;
used[i] = timer;
}
}
bal = 0;
for (int i = r; i >= l; --i)
{
if (used[i] == timer)
continue;
if (s[i] == 'C')
++bal;
else
--bal;
if (bal < 0)
{
++ans;
++bal;
used[i] = timer;
}
}
cout << ans << "\n";
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int tt = 1;
// cin >> tt;
for (int i = 1; i <= tt; ++i)
{
solve();
}
return 0;
}
