#include <bits/stdc++.h>
#define N 500005
using namespace std;
vector<pair<int,int>> query[N];
int ans[N];
int suf[N];
struct SegTree{
vector<int> t,lazy;
int n;
SegTree(int size){
n = size;
t.assign(4*n,1e9);
lazy.assign(4*n,0);
}
void push(int v){
t[v*2] += lazy[v];
lazy[v*2] += lazy[v];
t[v*2+1] += lazy[v];
lazy[v*2+1] += lazy[v];
lazy[v] = 0;
}
void upd(int v,int tl,int tr,int l,int r,int val){
if(tr < l || r < tl)
return;
if(l <= tl && tr <= r){
t[v] += val;
lazy[v] += val;
return;
}
push(v);
int tm = (tl + tr)/2;
upd(v*2,tl,tm,l,r,val);
upd(v*2+1,tm+1,tr,l,r,val);
t[v] = min(t[v*2],t[v*2+1]);
}
int get(int v,int tl,int tr,int l,int r){
if(tr < l || r < tl)
return 1e9;
if(l <= tl && tr <= r)
return t[v];
push(v);
int tm = (tl + tr)/2;
return min(get(v*2,tl,tm,l,r),get(v*2+1,tm+1,tr,l,r));
}
void upd(int l,int r,int val){
upd(1,1,n,l,r,val);
}
int get(int l,int r){
return get(1,1,n,l,r);
}
};
struct BIT{
vector<int> bit;
int n;
BIT(int size){
n = size + 5;
bit.assign(n,0);
}
void upd(int pos,int val){
for(;pos < n;pos += pos & -pos)
bit[pos] += val;
}
int get(int pos){
int ret = 0;
for(;pos > 0;pos -= pos & -pos)
ret += bit[pos];
return ret;
}
int get(int l,int r){
return get(r) - get(l-1);
}
};
void solve(){
int n,q;
string s;
cin >> n >> s >> q;
s = "." + s;
for(int i = n;i>=1;i--){
suf[i] = suf[i+1] + (s[i] =='C'?1:-1);
//cout << i << " " << suf[i] << endl;
}
for(int i = 1;i<=q;i++){
int l,r;
cin >> l >> r;
query[l].push_back({r,i});
}
SegTree t(n);
BIT bt(n);
vector<int> nodes;
for(int i = n;i>=1;i--){
if(s[i] == 'C'){
if(nodes.size()){
bt.upd(nodes.back(),-1);
t.upd(i+1,nodes.back(),-1);
nodes.pop_back();
}
}
if(s[i] == 'T'){
bt.upd(i,1);
nodes.push_back(i);
}
t.upd(i,i,(int) - 1e9 + suf[i] + nodes.size());
for(auto u:query[i]){
int tot = bt.get(i,u.first);
tot += max(0,-(t.get(i,u.first) - suf[u.first+1] - bt.get(u.first+1,n)));
ans[u.second] = tot;
}
/*
cout << "i: " << i << endl;
for(int j = i;j<=n;j++){
cout << t.get(j,j) << " ";
}
cout << endl;*/
}
for(int i = 1;i<=q;i++){
cout << ans[i] << "\n";
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#ifdef Local
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t = 1;
//cin >> t;
while(t--){
solve();
}
#ifdef Local
cout << endl << fixed << setprecision(2) << 1000.0 * clock() / CLOCKS_PER_SEC << " milliseconds.";
#endif
}
