#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 200010;
const int inf = 1e13;
int n, a[N], bit[N];
void update(int u, int v) {
int idx = u;
while (idx <= n) {
bit[idx] += v;
idx += (idx & (-idx));
}
}
int getSum(int p) {
int idx = p, ans = 0;
while (idx > 0) {
ans += bit[idx];
idx -= (idx & (-idx));
}
return ans;
}
struct Segtree {
vector<int> x, st, st_l, st_r;
Segtree(int m) {
x.assign(m, 0);
st.assign(4 * m, 0);
st_l.assign(4 * m, 0);
st_r.assign(4 * m, 0);
}
void build(int id, int l, int r) {
if (l == r) {
st[id] = x[l];
st_l[id] = l;
st_r[id] = r;
return;
}
int mid = (l + r) / 2;
build(id * 2, l, mid);
build(id * 2 + 1, mid + 1, r);
st[id] = max(st[id * 2], st[id * 2 + 1]);
if (st[id * 2] == st[id * 2 + 1]) {
st_l[id] = st_l[id * 2];
st_r[id] = st_r[id * 2 + 1];
} else if (st[id * 2] < st[id * 2 + 1]) {
st_l[id] = st_l[id * 2 + 1];
st_r[id] = st_r[id * 2 + 1];
} else {
st_l[id] = st_l[id * 2];
st_r[id] = st_r[id * 2];
}
}
pair<int, int> get_l(int id, int l, int r, int u, int v) {
if (r < u || v < l) return {- inf, 0};
if (u <= l && r <= v) {
return {st[id], st_l[id]};
}
int mid = (l + r) / 2;
pair<int, int> ans_1 = get_l(id * 2, l, mid, u, v);
pair<int, int> ans_2 = get_l(id * 2 + 1, mid + 1, r, u, v);
if (ans_1.second < ans_2.second) return ans_2;
return ans_1;
}
pair<int, int> get_r(int id, int l, int r, int u, int v) {
if (r < u || v < l) return {- inf, 0};
if (u <= l && r <= v) {
return {st[id], st_r[id]};
}
int mid = (l + r) / 2;
pair<int, int> ans_1 = get_r(id * 2, l, mid, u, v);
pair<int, int> ans_2 = get_r(id * 2 + 1, mid + 1, r, u, v);
if (ans_1.second > ans_2.second) return ans_1;
return ans_2;
}
} ;
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
char c;
for (int i = 1; i <= n; i ++) {
cin >> c;
if (c == 'T') {
a[i] = 1;
update(i, 1);
} else {
a[i] = - 1;
}
}
Segtree seg1(n + 10), seg2(n + 10);
int cur = 0;
for (int i = 1; i <= n; i ++) {
cur += a[i];
seg1.x[i] = cur;
}
seg1.build(1, 1, n);
cur = 0;
for (int i = n; i >= 1; i --) {
cur += a[i];
seg2.x[i] = cur;
}
seg2.build(1, 1, n);
int q, l, r;
cin >> q;
while (q --) {
cin >> l >> r;
pair<int, int> m1 = seg1.get_l(1, 1, n, l, r);
pair<int, int> m2 = seg2.get_r(1, 1, n, l, r);
if (m1.first == - inf && m2.first == - inf) {
cout << 0 << "\n";
} else if (m1.first == - inf) {
cout << seg2.x[m2.second] - seg2.x[r + 1] << "\n";
} else if (m2.first == - inf) {
cout << seg1.x[m1.second] - seg1.x[l - 1] << "\n";
} else {
cout << max(seg1.x[m1.second] - seg1.x[l - 1], seg2.x[m2.second] - seg2.x[r + 1]) << "\n";
}
}
return 0;
}
