#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
#define ll long long
#define pb push_back
#define sz(x) (int)(x).size()
#define mp make_pair
#define f first
#define s second
#define all(x) x.begin(), x.end()
#define D(x) cerr << #x << " is " << (x) << "\n";
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>; ///find_by_order(),order_of_key()
template<class T1, class T2> ostream& operator<<(ostream& os, const pair<T1,T2>& a) { os << '{' << a.f << ", " << a.s << '}'; return os; }
template<class T> ostream& operator<<(ostream& os, const vector<T>& a){os << '{';for(int i=0;i<sz(a);i++){if(i>0&&i<sz(a))os << ", ";os << a[i];}os<<'}';return os;}
template<class T> ostream& operator<<(ostream& os, const deque<T>& a){os << '{';for(int i=0;i<sz(a);i++){if(i>0&&i<sz(a))os << ", ";os << a[i];}os<<'}';return os;}
template<class T> ostream& operator<<(ostream& os, const set<T>& a) {os << '{';int i=0;for(auto p:a){if(i>0&&i<sz(a))os << ", ";os << p;i++;}os << '}';return os;}
template<class T> ostream& operator<<(ostream& os, const set<T,greater<T> >& a) {os << '{';int i=0;for(auto p:a){if(i>0&&i<sz(a))os << ", ";os << p;i++;}os << '}';return os;}
template<class T> ostream& operator<<(ostream& os, const multiset<T>& a) {os << '{';int i=0;for(auto p:a){if(i>0&&i<sz(a))os << ", ";os << p;i++;}os << '}';return os;}
template<class T> ostream& operator<<(ostream& os, const multiset<T,greater<T> >& a) {os << '{';int i=0;for(auto p:a){if(i>0&&i<sz(a))os << ", ";os << p;i++;}os << '}';return os;}
template<class T1,class T2> ostream& operator<<(ostream& os, const map<T1,T2>& a) {os << '{';int i=0;for(auto p:a){if(i>0&&i<sz(a))os << ", ";os << p;i++;}os << '}';return os;}
const int N=5e5+5;
vector<pair<int,int> > mxpre(4*N),mxsuf(4*N);
vector<int> prearr(N),sufarr(N),cnt(N);
void initpre(int l=0,int r=N-1,int i=1){
if(l==r){
mxpre[i]={prearr[l],N-l};
return;
}
int m=(l+r)>>1;
initpre(l,m,2*i);
initpre(m+1,r,2*i+1);
mxpre[i]=max(mxpre[2*i],mxpre[2*i+1]);
}
pair<int,int> getpre(int qs,int qe,int l=0,int r=N-1,int i=1){
if(qs>r||qe<l)
return {INT_MIN,INT_MIN};
if(qs<=l&&qe>=r)
return mxpre[i];
int m=(l+r)>>1;
return max(getpre(qs,qe,l,m,2*i),getpre(qs,qe,m+1,r,2*i+1));
}
void initsuf(int l=0,int r=N-1,int i=1){
if(l==r){
mxsuf[i]={sufarr[l],l};
return;
}
int m=(l+r)>>1;
initsuf(l,m,2*i);
initsuf(m+1,r,2*i+1);
mxsuf[i]=max(mxsuf[2*i],mxsuf[2*i+1]);
}
pair<int,int> getsuf(int qs,int qe,int l=0,int r=N-1,int i=1){
if(qs>r||qe<l)
return {INT_MIN,INT_MIN};
if(qs<=l&&qe>=r)
return mxsuf[i];
int m=(l+r)>>1;
return max(getsuf(qs,qe,l,m,2*i),getsuf(qs,qe,m+1,r,2*i+1));
}
int get(int l,int r){
if(l>r)
return 0;
int ans=cnt[r];
if(l)
ans-=cnt[l-1];
return ans;
}
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
int n,q;
string s;
cin >> n >> s >> q;
string t=s;
for(int i=0;i<q;i++){
int l,r;
cin >> l >> r;
l--;r--;
int ans=0,sum=0;
for(int j=l;j<=r;j++){
if(t[j]=='C')
sum++;
if(t[j]=='T')
sum--;
if(sum<0)
sum++,t[j]='X',ans++;
}
sum=0;
for(int j=r;j>=l;j--){
if(t[j]=='C')
sum++;
if(t[j]=='T')
sum--;
if(sum<0)
sum++,t[j]='X',ans++;
}
for(int j=l;j<=r;j++)
t[j]=s[j];
printf("%i\n",ans);
}
return 0;
}
