/*
Ben Watson
Quang Minh MasterDDDDD
*/
#include <bits/stdc++.h>
using namespace std;
#define ll long long
const string name = "test";
void solve();
signed main()
{
if (fopen((name + ".inp").c_str(), "r"))
{
freopen((name + ".inp").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
solve();
return 0;
}
// main program
const int maxn = 5e5 + 1;
struct Node
{
int pre, suff, sum, finals;
Node() : finals(-1) {};
Node(int val)
{
pre = suff = finals = max(0, val);
sum = val;
}
Node operator + (const Node& other)
{
Node res;
if (other.finals == -1) return (*this);
if (finals == -1) return other;
res.sum = sum + other.sum;
res.pre = max(pre, sum + other.pre);
res.suff = max(other.suff, other.sum + suff);
res.finals = max({pre + other.suff, finals + other.sum, sum + other.finals});
return res;
}
};
struct SegmentTree
{
vector<Node> st;
int n;
SegmentTree(int n, int *arr) : n(n)
{
st.resize(4 * n + 1);
build(1, 1, n, arr);
}
void build(int head, int l, int r, int *arr)
{
if (l == r)
{
st[head] = Node(arr[l]);
return;
}
int mid = l + r >> 1;
build(head << 1, l, mid, arr);
build(head << 1 | 1, mid + 1, r, arr);
st[head] = st[head << 1] + st[head << 1 | 1];
}
Node query(int head, int l, int r, int u, int v)
{
if (l > v || r < u) return Node();
if (u <= l && r <= v) return st[head];
int mid = l + r >> 1;
return query(head << 1, l, mid, u, v) + query(head << 1 | 1, mid + 1, r, u, v);
}
int query(int u, int v) { Node res = query(1, 1, n, u, v); return res.finals; }
};
int a[maxn];
int n, q;
void solve()
{
cin >> n;
for (int i = 1; i <= n; i++)
{
char c; cin >> c;
a[i] = (c == 'T' ? 1 : -1);
}
SegmentTree st(n, a);
cin >> q;
while (q--)
{
int l, r; cin >> l >> r;
cout << st.query(l, r) << '\n';
}
}
