#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;
using ll = long long;
const int N = 500'000 + 10;
struct LazySegTree {
struct Node {
int val = 0;
int lazy = 0;
Node() {};
Node(int _val, int _lazy): val(_val), lazy(_lazy) {};
Node operator+(const Node& other) const {
Node res;
res.val = max(this->val, other.val);
return res;
}
};
int n_node = 0;
vector<Node> tree = {};
void resize(int _n) { n_node = _n; tree.resize((n_node << 2) + 10); };
LazySegTree() {};
LazySegTree(int _n) { this->resize(_n); };
void down(int node, int l, int r) {
tree[node].val += tree[node].lazy;
if (l < r) {
tree[node << 1].lazy += tree[node].lazy;
tree[node << 1 | 1].lazy += tree[node].lazy;
}
tree[node].lazy = 0;
}
void update(int node, int l, int r, int L, int R, int val) {
down(node, l, r);
if (l > r || L > R || l > R || L > r) return;
if (L <= l && r <= R) {
tree[node].lazy += val;
down(node, l, r);
return;
}
int mid = (l + r) >> 1;
update(node << 1, l, mid, L, R, val);
update(node << 1 | 1, mid + 1, r, L, R, val);
tree[node] = tree[node << 1] + tree[node << 1 | 1];
}
void Update(int l, int r, int val) {
return update(1, 1, n_node, l, r, val);
}
Node query(int node, int l, int r, int L, int R) {
down(node, l, r);
if (l > r || L > R || l > R || L > r) return Node(-1'000'000'000, 0);
if (L <= l && r <= R) return tree[node];
int mid = (l + r) >> 1;
return query(node << 1, l, mid, L, R) + query(node << 1 | 1, mid + 1, r, L, R);
}
Node Query(int l, int r) {
return query(1, 1, n_node, l, r);
}
};
struct FenWick {
int n_node = 0;
vector<int> tree = {};
void resize(int n) { n_node = n; tree.resize(n + 10, 0); }
FenWick() {};
FenWick(int n) { this -> resize(n); };
void Update(int idx, int val) {
for( ; idx <= n_node; idx += (idx & - idx)) tree[idx] += val;
return;
}
int Query(int idx) {
int res = 0;
for( ; idx > 0; idx -= (idx & - idx)) res += tree[idx];
return res;
}
int Sum_to(int l, int r) {
if(l > r) return 0;
return Query(r) - Query(l - 1);
}
int kth(int val) {
int res = 0, s = 0;
for(int mask = 30; mask >= 0; -- mask) {
int nxt = res | (1 << mask);
if(nxt < n_node && s + tree[nxt] < val) {
res = nxt;
s += tree[nxt];
}
}
++ res; return res;
}
void reset(int idx) {
for ( ; idx <= n_node; idx += (idx & - idx)) tree[idx] = 0;
return;
}
};
int n, q;
string s;
int pred[N];
vector<pair<int, int>> events[N];
int lft[N];
int res[N];
void solve() {
cin >> n >> s; s = ' ' + s;
for (int i = 1; i <= n; ++i) {
pred[i] = pred[i - 1] + (s[i] == 'C' ? 1 : -1);
}
stack<int> stk;
for (int i = n; i >= 1; --i) {
if (s[i] == 'T') {
stk.push(i);
} else {
if (!stk.empty()) {
lft[stk.top()] = i;
stk.pop();
}
}
}
while (!stk.empty()) {
stk.pop();
}
LazySegTree st(n);
for (int i = 1; i <= n; ++i) {
st.Update(i, i, pred[i]);
}
cin >> q;
for (int i = 1; i <= n; ++i) {
if (lft[i] != 0) {
events[lft[i]].push_back(make_pair(i, -1));
}
}
for (int i = 1; i <= q; ++i) {
int l, r; cin >> l >> r;
events[l].push_back(make_pair(r, i));
}
FenWick bit(n);
for (int l = n; l >= 1; --l) {
if (s[l] == 'T') {
stk.push(l);
st.Update(l, n, 1);
bit.Update(l, 1);
if (lft[l] > 0) {
bit.Update(lft[l], -1);
}
}
for (const auto& [r, idx] : events[l]) {
if (idx == -1) {
st.Update(r, n, -1);
} else {
int max_pref = max(pred[l - 1], st.Query(l, r - 1).val);
// cerr << idx << ' ' << max_pref << ' ' << st.Query(r, r).val << '\n';
res[idx] = bit.Sum_to(l, r) + max(0, max_pref - st.Query(r, r).val);
}
}
}
for (int i = 1; i <= q; ++i) {
cout << res[i] << '\n';
}
}
int32_t main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr); std::cout.tie(nullptr);
// int t; cin >> t;
int t = 1;
while (t-- > 0) {
solve();
// cout << '\n';
}
return (0 ^ 0);
}
/// Code by vuavisao
