#include <bits/stdc++.h>
using i64 = long long;
struct Info {
int mxpre, mxsuf, sum, ans;
Info() { *this = Info(0); }
Info(int x) {
ans = mxsuf = mxpre = std::max(0, x);
sum = x;
}
};
Info operator+(Info lhs, Info rhs) {
Info res;
res.mxpre = std::max(lhs.mxpre, lhs.sum + rhs.mxpre);
res.mxsuf = std::max(lhs.mxsuf + rhs.sum, rhs.mxsuf);
res.sum = lhs.sum + rhs.sum;
res.ans = std::max({lhs.ans + rhs.sum, lhs.sum + rhs.ans, lhs.mxpre + rhs.mxsuf});
return res;
}
template<typename T>
struct SegTree {
int n;
std::vector<T> tree;
SegTree(int n) : n(n) {
tree.resize(4 * n);
}
void set(int node, int l, int r, int p, T v) {
if(l == r) {
tree[node] = v;
return;
}
int mid = (l + r) / 2;
if(p <= mid) {
set(node * 2, l, mid, p, v);
} else {
set(node * 2 + 1, mid + 1, r, p, v);
}
tree[node] = tree[node * 2] + tree[node * 2 + 1];
}
void set(int p, T v) {
set(1, 0, n - 1, p, v);
}
T query(int node, int l, int r, int ql, int qr) {
if(ql <= l && r <= qr) {
return tree[node];
}
int mid = (l + r) / 2;
if(qr <= mid) {
return query(node * 2, l, mid, ql, qr);
} else if(mid + 1 <= ql) {
return query(node * 2 + 1, mid + 1, r, ql, qr);
}
return query(node * 2, l, mid, ql, qr) + query(node * 2 + 1, mid + 1, r, ql, qr);
}
T query(int l, int r) {
return query(1, 0, n - 1, l, r);
}
};
void solve() {
int n;
std::cin >> n;
std::string s;
std::cin >> s;
SegTree<Info> st(n);
std::vector<int> v(n);
for(int i = 0; i < n; i++) {
v[i] = (s[i] == 'T' ? 1 : -1);
st.set(i, Info(v[i]));
}
int q;
std::cin >> q;
for(int _ = 0; _ < q; _++) {
int l, r;
std::cin >> l >> r;
l--; r--;
std::cout << st.query(l, r).ans << "\n";
}
return;
}
signed main() {
#ifdef LOCAL
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
#endif
std::ios_base::sync_with_stdio(false);
std::cin.tie(NULL); std::cout.tie(NULL);
int t = 1; //std::cin >> t;
for(int i = 1; i <= t; i++) {
solve();
}
return 0;
}
