#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define ull unsigned long long
#define pii pair<int,int>
#define pll pair<long long, long long>
#define fi first
#define se second
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define lwb lower_bound
#define upb upper_bound
#define TASKNAME "NAME"
void init()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
///freopen(TASKNAME".INP","r",stdin); freopen(TASKNAME".OUT","w",stdout);
}
const int SZ = 5e5+5;
const ll INF = INT_MAX / 2, MOD = 1e9+7, INFLL = 2e18;
const double epsilon = 1e-3;
int n, a[SZ];
string s;
struct SegTree
{
struct Node
{
int sum, pref, suff, res;
Node operator + (const Node& other) const
{
Node cur;
cur.sum = sum + other.sum;
cur.pref = max(pref, sum + other.pref);
cur.suff = max(other.suff, other.sum + suff);
cur.res = max({ res + other.sum, other.res + sum, pref + other.suff });
return cur;
}
} nodes[4*SZ];
void build(int id = 1, int lo = 1, int hi = n)
{
if(lo == hi)
{
if(s[lo] == 'T') nodes[id] = {1, 1, 1, 1};
else nodes[id] = {-1, 0, 0, 0};
return;
}
int mid = (lo + hi) / 2;
build(2*id, lo, mid);
build(2*id+1, mid+1, hi);
nodes[id] = nodes[2*id] + nodes[2*id+1];
}
Node query(int u, int v, int id = 1, int lo = 1, int hi = n)
{
if(lo > v || hi < u) return {0,0,0,0};
if(lo >= u && hi <= v) return nodes[id];
int mid = (lo + hi) / 2;
return query(u, v, 2*id, lo, mid) + query(u,v, 2*id+1, mid+1, hi);
}
} st;
int main()
{
init();
cin >> n >> s;
s = " " + s;
st.build();
int q;
cin >> q;
while(q--)
{
int lo,hi;
cin >> lo >> hi;
cout << st.query(lo, hi).res << '\n';
}
}
