#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
const int mxN=5e5;
int n, q, ans[mxN];
string s;
ar<int, 2> st[1<<20];
vector<ar<int, 2>> queries[mxN];
vector<int> stk;
ar<int, 2> cmb(ar<int, 2> a, ar<int, 2> b) {
return {a[0]+b[0], min(a[1], a[0]+b[1])};
}
void upd(int i, int x, int u=1, int l=0, int r=n-1) {
if (l==r) {
st[u][0]=x;
st[u][1]=min(0, st[u][0]);
return;
}
int mid=(l+r)/2;
i<=mid?upd(i, x, 2*u, l, mid):upd(i, x, 2*u+1, mid+1, r);
st[u]=cmb(st[2*u], st[2*u+1]);
}
ar<int, 2> qry(int ql, int qr, int u=1, int l=0, int r=n-1) {
if (l>qr||r<ql)
return {};
if (ql<=l&&r<=qr)
return st[u];
int mid=(l+r)/2;
return cmb(qry(ql, qr, 2*u, l, mid), qry(ql, qr, 2*u+1, mid+1, r));
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> s >> q;
for (int i=0; i<q; ++i) {
int l, r;
cin >> l >> r, --l, --r;
queries[r].push_back({l, i});
}
for (int i=0; i<n; ++i) {
if (s[i]=='C') {
upd(i, 1);
if (stk.size()) {
upd(stk.back(), -1);
stk.pop_back();
}
} else {
upd(i, 0);
stk.push_back(i);
}
for (auto [l, ind] : queries[i]) {
int x=stk.end()-lower_bound(stk.begin(), stk.end(), l);
ans[ind]=x-qry(l, i)[1];
}
}
for (int i=0; i<q; ++i)
cout << ans[i] << "\n";
return 0;
}
