#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 500100;
vector<pair<int,int>>events[maxn];
int arr[maxn], answer[maxn], n, q;
struct node {
public:
int l, r;
int sum, minsuf;
} tree[4*maxn];
node mergef(node a, node b) {
node c;
c.l = a.l; c.r = b.r;
c.sum = a.sum + b.sum;
c.minsuf = min(b.minsuf, a.minsuf + b.sum);
return c;
}
void build(int li=1, int ri=n, int index=1) {
if(li == ri) {
tree[index].l = li; tree[index].r = ri;
tree[index].sum = arr[li];
tree[index].minsuf = min(0, arr[li]);
}
else {
int mid = (li+ri)/2;
build(li, mid, 2*index);
build(mid+1,ri,2*index+1);
tree[index] = mergef(tree[2*index], tree[2*index+1]);
}
/*cout<<index<<": ["<<li<<", "<<ri<<"]\n";
cout<<tree[index].sum<<" "<<tree[index].minsuf<<"\n";*/
}
node query(int ql, int qr, int index=1) {
if(qr < tree[index].l || tree[index].r < ql) return {0,0,0,4*maxn};
else if(tree[index].l >= ql && tree[index].r <= qr) return tree[index];
else {
return mergef(query(ql,qr,2*index), query(ql,qr,2*index+1));
}
}
void update(int ul, int val, int index=1) {
if(tree[index].l == tree[index].r) {
arr[ul] = val;
tree[index].sum = val;
tree[index].minsuf = min(val, 0);
}
else {
int mid = (tree[index].l+tree[index].r)/2;
if(ul <= mid) update(ul,val,2*index);
else update(ul,val,2*index+1);
tree[index] = mergef(tree[2*index], tree[2*index+1]);
}
}
int main() {
cin>>n;
char c;
for(int i=1;i<=n;i++) {
cin>>c;
if(c == 'C') arr[i] = 1;
else arr[i] = -1;
}
build();
cin>>q;
int l, r;
for(int i=1;i<=q;i++) {
cin>>l>>r;
events[l].pb(mp(r,i));
}
vector<int>st;
for(int i=n;i>=1;i--) {
if(arr[i] == -1) {
update(i, 0);
st.pb(i);
}
else if(arr[i] == 1 && st.size()>0) {
update(st.back(), -1);
st.pop_back();
}
/*cout<<i<<": \n";
for(int i:st) cout<<i<<" ";
cout<<"\n Suffix: "<<query(i, n).minsuf<<"\n";*/
for(auto j:events[i]) {
l = i, r = j.first;
answer[j.second] = upper_bound(st.rbegin(), st.rend(), r) - st.rbegin() - query(l, r).minsuf;
}
}
for(int i=1;i<=q;i++) {
cout<<answer[i]<<"\n";
}
return 0;
}
