// __builtin_popcount(x) broj bitova
// __builtin_popcountll(x) long long
#define here cerr<<"---------------------------\n"
#include "bits/stdc++.h"
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#define ld double
#define ll long long
#define ull unsigned long long
#define llinf 100000000000000000LL // 10^17
#define iinf 2000000000 // 2*10^9
#define pb push_back
#define popb pop_back
#define fi first
#define sc second
#define endl '\n'
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pld pair<ld,ld>
#define sz(a) int(a.size())
#define all(a) a.begin(),a.end()
#define rall(a) a.begin(),a.end(),greater<int>()
#define getunique(v) {sort(all(v)); v.erase(unique(all(v)), v.end());}
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
void setIO(string inoutname)
{
freopen((inoutname+".in").c_str(),"r",stdin);
freopen((inoutname+".out").c_str(),"w",stdout);
}
#define mod 1
ll gcd(ll a, ll b)
{
if(b==0) return a;
if(a==0) return b;
if(a>=b) return gcd(a%b,b);
return gcd(a,b%a);
}
ll lcm(ll a,ll b){
return (a/gcd(a,b))*b;
}
ll add(ll a,ll b){
a+=b;
a+=mod;
if(a>=mod) a%=mod;
return a;
}
ll mul(ll a,ll b){return(a*b)%mod;}
#define maxn 500005
ll n,q;
ll a[maxn];
struct node{
ll l,r,s,ans;
node operator+(node b){
node rez;
rez.l = max(l,s+b.l);
rez.r = max(b.r,r+b.s);
rez.s = s + b.s;
rez.ans = max({l+b.r,ans+b.s,s+b.ans});
return rez;
}
};
node t[4*maxn];
void init(ll v,ll tl,ll tr){
if(tl==tr){
if(a[tl]==1) t[v] = {1,1,1,1};
else t[v] = {0,0,-1,0};
return;
}
ll mid = (tl+tr)/2;
init(2*v,tl,mid);
init(2*v+1,mid+1,tr);
t[v] = t[2*v]+t[2*v+1];
}
node reshi(ll v,ll tl,ll tr,ll l,ll r){
if(l>r) return {0,0,0,0};
if(tl==l&&tr==r) return t[v];
ll mid = (tl+tr)/2;
return reshi(2*v,tl,mid,l,min(mid,r)) + reshi(2*v+1,mid+1,tr,max(l,mid+1),r);
}
void tc(){
ios_base::sync_with_stdio(false);cerr.tie(0);cout.tie(0);cin.tie(0);
cin >> n;
for(ll i = 1;i<=n;i++){
char c;
cin >> c;
if(c=='T') a[i] = 1;
else a[i] = -1;
}
init(1,1,n);
cin >> q;
while(q--){
ll l,r; cin >> l >> r;
cout<<reshi(1,1,n,l,r).ans<<endl;
}
}
int main(){
ios_base::sync_with_stdio(false);cerr.tie(0);cout.tie(0);cin.tie(0);
//setIO("lol");
int t; t = 1;
while(t--){
tc();
}
return 0;
}
