#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
int main()
{
ios::sync_with_stdio(0);
cin.tie(NULL), cout.tie(NULL);
int n;
cin>>n;
string s;
cin>>s;
int q;
cin>>q;
bool dis[n]={};
while (q--)
{
int l,r;
cin>>l>>r;l--,r--;
for (int i=l;i<=r;i++) dis[i]=0;
int ans=0,cnt=0;
for (int i=l;i<=r;i++)
{
cnt+=(s[i]=='C')-(s[i]=='T');
if (cnt<0) ans++,cnt++,dis[i]=1;
}
cnt=0;
for(int i=r;i>=l;i--)
{
if (dis[i]) continue;
cnt+=(s[i]=='C')-(s[i]=='T');
if (cnt<0) ans++,cnt++,dis[i]=1;
}
cout<<ans<<endl;
}
return 0;
}
