#include<iostream>
#include<stdio.h>
#include<stdint.h>
#include<iomanip>
#include<algorithm>
#include<utility>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<deque>
#include<math.h>
#include<assert.h>
#include<string.h>
using namespace std;
const int64_t INF = (int64_t) 1e18 + 100;
const int64_t mINF = (int64_t) 1e6 * 2 + 100;
const int64_t MOD = 1e9 + 7;
const int64_t MOD2 = 998244353;
const int nbit = 31;
const int ndig = 10;
const int nchar = 26;
const int D = 4;
int dr[D] = {-1, 0, 1, 0};
int dc[D] = {0, 1, 0, -1};
const int Dk = 8;
int drk[Dk] = {2, 2, -2, -2, 1, 1, -1, -1};
int dck[Dk] = {1, -1, 1, -1, 2, -2, 2, -2};
struct Node
{
int mx;
int sum;
int pre;
int suf;
Node(int mx_, int sum_, int pre_, int suf_) : mx(mx_), sum(sum_), pre(pre_), suf(suf_) {}
};
struct Solution
{
int n;
string s;
vector<Node> tree;
Solution() {}
void solve()
{
cin >> n >> s;
while(__builtin_popcount(n) != 1) n++;
tree.resize(2 * n, Node(0, 0, 0, 0));
for(int i = 0; i < (int) s.length(); i++)
{
if(s[i] == 'T') tree[n + i] = Node(1, 1, 1, 1);
else tree[n + i] = Node(0, -1, 0, 0);
}
for(int i = n - 1; i >= 1; i--)
{
tree[i] = combine(tree[i * 2], tree[i * 2 + 1]);
}
int q;
cin >> q;
for(int i = 0; i < q; i++)
{
int l;
int r;
cin >> l >> r;
l--; r--;
cout << get(1, 0, n - 1, l, r).mx << "\n";
}
}
Node get(int node, int nleft, int nright, int left, int right)
{
if(left > nright || nleft > right) return Node(0, 0, 0, 0);
if(left <= nleft && nright <= right) return tree[node];
int mid = nleft + (nright - nleft) / 2;
return combine(get(node * 2, nleft, mid, left, right),
get(node * 2 + 1, mid + 1, nright, left, right));
}
Node combine(Node left, Node right)
{
Node now(0, 0, 0, 0);
now.sum = left.sum + right.sum;
now.pre = max(left.pre, left.sum + right.pre);
now.suf = max(right.suf, right.sum + left.suf);
now.mx = max({left.mx + right.sum, left.sum + right.mx, left.pre + right.suf});
return now;
}
void modadd(int& t1, int t2)
{
t1 += t2;
if(t1 >= MOD) t1-= MOD;
return;
}
void modsub(int& t1, int t2)
{
t1 -= t2;
if(t1 < 0) t1 += MOD;
return;
}
int modmul(int t1, int t2)
{
int64_t res = 1LL * t1 * t2;
return res % MOD;
}
int Abs(int tmp)
{
if(tmp < 0) return -tmp;
return tmp;
}
int MASK(int j)
{
return (1 << j);
}
int BIT(int tmp, int j)
{
int x = tmp & MASK(j);
if(x != 0) return 1;
return 0;
}
};
void __setup()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
}
int main()
{
__setup();
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
Solution().solve();
}
return 0;
}
