#include <bits/stdc++.h>
using namespace std;
vector<int> solutions;
int main() {
int n;
cin >> n;
vector<char> el(n);
for (int i = 0; i < n; ++i) {
cin >> el[i];
}
int q;
cin >> q;
for (int i = 0; i < q; ++i) {
int a, b;
cin >> a >> b;
vector<int> removeclump, removeclump1;
int currcs = 0;
int currts = 0;
bool cstate = true;
vector<int> csandts;
for (int i = a - 1; i < b; ++i) {
if (el[i] == 'C' and !cstate) {
removeclump.push_back(currts - currcs + min((removeclump.size() > 0 ? removeclump.back() : 0), 0));
csandts.push_back(currts);
currcs = 1;
currts = 0;
cstate = true;
} else if (el[i] == 'C') {
++currcs;
} else if (el[i] == 'T') {
if (cstate) {
cstate = false;
csandts.push_back(currcs);
}
++currts;
}
}
if (!cstate) {
removeclump.push_back(currts - currcs + min((removeclump.size() > 0 ? removeclump.back() : 0), 0));
}
if (currts != 0 and !cstate) {
csandts.push_back(currts);
}
if (cstate and currcs != 0) {
csandts.push_back(currcs);
}
// FROM BACK
bool startt = (el[b - 1] == 'T');
int ts = 0;
int crs = 0;
for (int i = csandts.size() - 1; i >= 0; --i) {
if (startt) {
ts += csandts[i];
removeclump1.push_back(ts - crs + min((removeclump1.size() > 0 ? removeclump1.back() : 0), 0));
ts = 0;
crs = 0;
startt = false;
} else {
crs += csandts[i];
startt = true;
}
}
// END BACK
int sum = 0;
int cs = removeclump.size();
for (int i = 0; i < cs; ++i) {
sum += max(max(0, removeclump[i]), max(0, removeclump1[cs - i - 1]));
}
solutions.push_back(sum);
}
for (int i: solutions) {
cout << i << endl;
}
}
