#include <bits/stdc++.h>
using namespace std;
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define int long long
struct Node {
int sum, ans, pref, suf;
};
struct SegTree {
int n;
vector<Node> tree;
vector<int> v;
SegTree(vector<int> _v) {
v = _v;
n = sz(v);
tree.resize(4*n+5);
build(1, 0, n-1);
}
Node merge(Node a, Node b) {
Node res;
res.sum = a.sum + b.sum;
res.pref = max({ (int)0, a.pref, a.sum + b.pref });
res.suf = max({ (int)0, b.suf, b.sum + a.suf });
res.ans = max({ a.pref + b.suf, a.ans + b.sum, a.sum + b.ans });
return res;
}
void build(int u, int tl, int tr) {
if(tl == tr) {
tree[u].ans = max(v[tl], (int)0);
tree[u].sum = v[tl];
tree[u].pref = tree[u].suf = max(v[tl], (int)0);
} else {
int tm = (tl + tr) / 2;
build(2*u, tl, tm);
build(2*u+1, tm+1, tr);
tree[u] = merge(tree[2*u], tree[2*u+1]);
}
}
Node query(int u, int tl, int tr, int l, int r) {
if(tl > tr || tl > r || l > tr) return Node{0, 0, 0, 0};
if(l <= tl && tr <= r) return tree[u];
int tm = (tl + tr) / 2;
return merge(query(2*u, tl, tm, l, r),query(2*u+1, tm+1, tr, l, r));
}
int query(int l, int r) {
return query(1, 0, n-1, l, r).ans;
}
};
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n;
cin >> n;
vector<int> v(n);
for(int i=0; i<n; i++) {
char ch;
cin >> ch;
v[i] = (ch == 'T' ? 1 : -1);
}
SegTree tree(v);
int q;
cin >> q;
while(q--) {
int l, r;
cin >> l >> r;
cout << tree.query(l-1, r-1) << '\n';
}
}
