#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i = a; i<int(b);++i)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define trav(a,c) for(auto a: c)
typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll,ll> pii;
int main(){
cin.sync_with_stdio(false);
ll n;
string str;
cin>>n;
cin>>str;
ll q;
cin>>q;
rep(i,0,q){
ll a,b;
cin>>a>>b;
a--;
ll diff = 0;
vector<bool> nullified(n);
rep(i,a,b){
if(str[i]=='C') diff++;
else diff--;
if(diff<0){
diff++;
nullified[i] = true;
}
}
diff = 0;
for(int i = b-1;i>=a;i--){
if(nullified[i]) continue;
if(str[i]=='C') diff++;
else diff--;
if(diff<0){
diff++;
nullified[i] = true;
}
}
ll ans = 0;
rep(i,a,b) ans += nullified[i];
cout<<ans<<endl;
}
}
