#include "bits/stdc++.h"
using namespace std;
#define rep(i,a,b) for(int i=(a); i<(b); ++i)
#define all(x) x.begin(),x.end()
#define sz(x) int(x.size())
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
struct segtree{
struct node{
int sm=0, L=0, R=0, A=0;
node operator+(node b){
return node{sm+b.sm,
max(L,sm+b.L),
max(b.R,b.sm+R),
max(max(sm+b.A,A+b.sm),L+b.R)};
}
};
int n;
vector<node> seg;
segtree(vi a){
n = 1;
while(n<sz(a))
n*=2;
seg.resize(n*2);
rep(i,0,sz(a)) seg[i+n] = {a[i],max(0,a[i]),max(0,a[i]),max(0,a[i])};
for(int i = n-1; i>0; --i) seg[i] = seg[i*2]+seg[i*2+1];
}
node query(int id, int l, int r, int ql, int qr){
if (r <= ql or l >= qr) return {};
else if (l >= ql and r <= qr) return seg[id];
else{
int mid = (l+r)/2;
return query(id*2,l,mid,ql,qr)+query(id*2+1,mid,r,ql,qr);
}
}
};
int main(){
cin.tie(NULL),cin.sync_with_stdio(false);
int n; cin >> n;
vi a(n);
string s; cin >> s;
rep(i,0,n){
a[i] = (s[i]=='T'?1:-1);
}
segtree seg(a);
int q; cin >> q;
while(q--){
int l,r; cin >> l >> r;
l--;
auto ret = seg.query(1,0,seg.n,l,r);
cout << ret.A << '\n';
}
}
