#include<bits/stdc++.h>
using namespace std;
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define dbg(x) cout << #x << '=' << x << '\n';
#define ll long long
#define sz size()
#define x first
#define y second
#define pi pair <int, int>
#define pii pair <int, pi>
#define vi vector <int>
const ll mod = 1e9 + 7;
int n, q, l, r, sum;
set <int> s;
string ss;
int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
cin>>n>>ss>>q;
//cout<<q<<endl;
for(int i=1; i<=q; i++){
s.clear();
sum=0;//cout<<l<<endl;
cin>>l>>r;
for(int ix=l-1; ix<=r-1; ix++){
if(ss[ix]=='C') sum++;
else sum--;
if(sum<0){
sum+=1;
s.insert(ix);
}
}
sum=0;
for(int ix=r-1; ix>=l-1; ix--){
if(ss[ix]=='C') sum++;
else if(s.find(ix)==s.end())sum--;
if(sum<0){
sum+=1;
s.insert(ix);
}
}
cout<<s.size()<<"\n";
}
}
