#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define fst first
#define snd second
#define pb push_back
#define SZ(x) (int)x.size()
#define ALL(x) x.begin(),x.end()
#define forn(i,a,b) for(int i = a; i<b;i++)
#define mset(a,v) memset(a,v,sizeof(a))
#define FIN ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
template< typename T >
using iset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
ll n;
vector<ll> psum;
vector<ll> ssum;
int main(){
cin>>n;
string s; cin>>s;
vector<ll> v(n); forn(i,0,n) v[i]=(s[i]=='C'?1:-1);
psum=v; forn(i,1,n) psum[i]+=psum[i-1];
ssum=v; for(int i = n-2; i>=0; i--) ssum[i]+=ssum[i+1];
ll q; cin>>q;
ll res = 0;
forn(i,0,q){
ll l ,r; cin>>l>>r; l--; r--;
res=0;
vector<bool> modif(n,false);
forn(j,l,r+1){
ll mypsum = psum[j]; if(l-1>=0) mypsum-=psum[l-1];
if(s[j]=='T'&&mypsum<0) res++,modif[j]=true;
}
ll acum = 0;
for(int j = r; j>=l; j--){
ll myssum = ssum[j]; if(r+1<n) myssum-=ssum[r+1];
if(modif[j]) acum++;
myssum+=acum;
if(s[j]=='T'&&myssum<0&&!modif[j]) res++;
}
cout<<res<<'\n';
}
}
