#include <bits/stdc++.h>
using namespace std; const int N = 500005;
int n, q;
char c[N];
struct node{
int pre,suf,sum,ans;
node operator + (node b) {
node res;
res.sum = sum + b.sum;
res.pre = max(pre, sum + b.pre);
res.suf = max(b.suf, b.sum + suf);
res.ans = max({b.ans + sum, b.sum + ans, pre + b.suf});
return res;
}
} seg[4*N];
void build(int x,int l,int r) {
if(l == r) {
if(c[l] == 'T') seg[x] = {1,1,1,1};
else seg[x] = {0,0,-1,0};
return;
}
int mid = (l+r)/2;
build(2*x,l,mid);
build(2*x+1,mid+1,r);
seg[x] = seg[2*x] + seg[2*x+1];
}
node query(int x,int l,int r,int i,int j) {
if(l > j || r < i) return {0,0,0,0};
if(l >= i && r <= j) return seg[x];
int mid = (l+r)/2;
return query(2*x,l,mid,i,j) + query(2*x+1,mid+1,r,i,j);
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n;
for(int i=1;i<=n;++i) cin >> c[i];
build(1,1,n);
cin >> q;
while(q--) {
int l,r;cin >> l >> r;
cout << query(1,1,n,l,r).ans << '\n';
}
return 0;
}
