// Alir3za.Zar3 -> Shiraz , Iran
#include <bits/stdc++.h>
using namespace std;
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
string s; cin >> s;
int q; cin >> q;
bool mrk[n];
while (q--)
{
int l,r; cin >> l >> r;
l--; r--;
memset(mrk,0,sizeof(mrk));
int out = 0 , k = 0;
for (int i=l; i<=r; i++)
{
if (s[i]=='C') k++;
else
{
if (k > 0) k--;
else
{
out++; mrk[i] = 1;
}
}
}
k = 0;
for (int i=r; i>=l; i--)
{
if (mrk[i]) continue;
if (s[i]=='C') k++;
else
{
if (k > 0) k--;
else
{
out++;
}
}
}
cout << out << '\n';
}
}
