#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, q, x, y;
string s;
struct NODE
{
int a, b, c, d;
inline NODE operator*(NODE inp)
{
NODE res;
res.a = max(this->a, this->c + inp.a);
res.b = max(this->b + inp.c, inp.b);
res.c = this->c + inp.c;
res.d = max({this->a + inp.b, this->d + inp.c, this->c + inp.d});\
return res;
}
};
struct SEGMENT_TREE
{
NODE tree[2000000];
inline void Build(int ind, int l, int r)
{
if (l == r)
{
tree[ind].a = tree[ind].b = tree[ind].d = (s[l] == 'T' ? 1 : 0);
tree[ind].c = (s[l] == 'T' ? 1 : -1);
return;
}
int m = (l + r) >> 1;
Build(ind << 1, l, m);
Build(ind << 1 | 1, m + 1, r);
tree[ind] = tree[ind << 1] * tree[ind << 1 | 1];
}
inline NODE Get(int ind, int l, int r, int x, int y)
{
if (r < x || y < l)
{
return NODE();
}
if (x <= l && r <= y)
{
return tree[ind];
}
int m = (l + r) >> 1;
return Get(ind << 1, l, m, x, y) * Get(ind << 1 | 1, m + 1, r, x, y);
}
} st;
int main()
{
setup();
cin >> n >> s >> q;
s = '#' + s;
st.Build(1, 1, n);
while (q--)
{
cin >> x >> y;
cout << st.Get(1, 1, n, x, y).d << "\n";
}
return 0;
}
