#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace __gnu_pbds;
using namespace std;
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()
// #define int long long
// #define int unsigned long long
// #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>
void open_file(string filename) {
freopen((filename + ".in").c_str(), "r", stdin);
freopen((filename + ".out").c_str(), "w", stdout);
}
// const ll mod = 1e9 + 7;
// const ll mod = 998244353;
const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 5 * 1e5 + 25;
struct node {
int sum, suff;
};
char c[maxN];
node t[4 * maxN];
vector<pii> qs[maxN];
node merge(node a, node b) {
node ans;
ans.sum = a.sum + b.sum;
ans.suff = min(b.suff, a.suff + b.sum);
return ans;
}
void update(int v, int tl, int tr, int pos, int val) {
if (tl == tr) {
t[v].sum = val;
t[v].suff = min(0, val);
return;
} int tm = (tl + tr) / 2;
if (pos <= tm) update(2 * v, tl, tm, pos, val);
else update(2 * v + 1, tm + 1, tr, pos, val);
t[v] = merge(t[2 * v], t[2 * v + 1]);
}
node getmin(int v, int tl, int tr, int l, int r) {
if (l > r) {
node tmp;
tmp.sum = tmp.suff = 0;
return tmp;
} if (tl == l && tr == r)
return t[v];
int tm = (tl + tr) / 2;
return merge(getmin(2 * v, tl, tm, l, min(r, tm)),
getmin(2 * v + 1, tm + 1, tr, max(l, tm + 1), r));
}
void solve() {
int n;
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> c[i];
if (c[i] == 'C') update(1, 1, n, i, 1);
else update(1, 1, n, i, -1);
} int q; cin >> q; int ans[q + 1];
for (int i = 1; i <= q; i++) {
int l, r; cin >> l >> r;
qs[l].pb({r, i});
} vector<int> st;
for (int i = n; i >= 1; i--) {
if (c[i] == 'T') {
st.pb(i);
update(1, 1, n, i, 0);
} else if (!st.empty()) {
update(1, 1, n, st.back(), -1);
st.pop_back();
} for (auto v : qs[i]) {
int mn = getmin(1, 1, n, i, v.ff).suff;
if (mn < 0) mn = -mn;
else mn = 0;
ans[v.sc] = mn + upper_bound(st.rbegin(), st.rend(), v.ff) - st.rbegin();
}
} for (int i = 1; i <= q; i++)
cout << ans[i] << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
int t = 1;
// cin >> t;
while (t--) {
solve();
cout << '\n';
}
return 0;
}
