#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#pragma GCC optimize("-O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#define ll long long
#define mp make_pair
#define pb push_back
#define ld long double
#define fi first
#define se second
#define pld pair<ld,ld>
#define pll pair<ll,ll>
#define pii pair<int,int>
#define y1 Enkognit
#define all(v) v.begin(),v.end()
using namespace std;
using namespace __gnu_pbds;
const ll MOD=1000000007;
ll n, m, k, T;
string s;
ll binpow(ll h,ll r)
{
ll l=1;
while (r)
{
if (r&1) l=(l*h)%MOD;
h=(h*h)%MOD;
r/=2;
}
return l;
}
struct node
{
int sum;
int ans;
int l, r;
node():l(0),r(0),sum(0),ans(0){};
node(int h):l(h),r(h),sum(h),ans(h){};
};
node d[2000001];
node operator + (node x,node y)
{
if (x.sum==-1e9) return y;
if (y.sum==-1e9) return x;
node n;
n.sum=x.sum+y.sum;
n.l=max(x.l, x.sum+y.l);
n.r=max(y.r, y.sum+x.r);
n.ans=max(max(x.ans + y.sum, y.ans + x.sum), x.l + y.r);
return n;
}
void build(int h,int l,int r)
{
if (l==r)
{
if (s[l]=='T')
{
d[h].l++;
d[h].r++;
d[h].sum++;
d[h].ans++;
}else
{
d[h].sum--;
}
return;
}
int w=(l+r)/2;
build(h*2,l,w);
build(h*2+1,w+1,r);
d[h]=d[h*2]+d[h*2+1];
}
node get(int h,int l,int r,int x,int y)
{
if (x>y) return node(-1e9);
if (l==x && y==r) return d[h];
int w=(l+r)/2;
return get(h*2,l,w,x,min(y,w))+get(h*2+1,w+1,r,max(x,w+1),y);
}
void solve()
{
cin >> n;
cin >> s;
s=' '+s;
build(1,1,n);
ll q;
cin >> q;
while (q--)
{
ll l, r;
cin >> l >> r;
cout << get(1,1,n,l,r).ans << "\n";
}
}
int main()
{
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
ios::sync_with_stdio(0);
cin.tie(0);
ll t=1;
//cin >> t;
while (t--)
{
solve();
}
return 0;
}
/*
11
CCCTTTTTTCC
3
1 11
4 9
1 6
*/
