#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#define int long long
const int MAXN = 500000 + 10;
int n, m;
std::string s;
int a[MAXN];
struct SegmentTree
{
struct Node
{
bool active;
int ans;
int inside;
int prefix;
int suffix;
Node()
{
active = false;
ans = inside = prefix = suffix = 0;
}
Node(int val)
{
active = true;
ans = (val == +1);
inside = val;
prefix = suffix = (val == +1);
}
inline friend Node operator + (const Node &left, const Node &right)
{
if(!left.active)
{
return right;
}
if(!right.active)
{
return left;
}
Node result;
result.active = true;
result.inside = left.inside + right.inside;
result.prefix = std::max(left.prefix, left.inside + right.prefix);
result.suffix = std::max(right.suffix, right.inside + left.suffix);
result.ans = std::max({left.ans + right.inside, left.inside + right.ans, left.prefix + right.suffix});
return result;
}
};
Node tree[4 * MAXN];
void build(int idx, int low, int high, int arr[])
{
if(low == high)
{
tree[idx] = Node(arr[low]);
return;
}
int mid = (low + high) / 2;
build(2 * idx, low, mid, arr);
build(2 * idx + 1, mid + 1, high, arr);
tree[idx] = tree[2 * idx] + tree[2 * idx + 1];
}
Node query(int idx, int low, int high, int qL, int qR)
{
if(qL > high || qR < low)
{
return Node();
}
else if(qL <= low && high <= qR)
{
return tree[idx];
}
int mid = (low + high) / 2;
Node res;
res = res + query(2 * idx, low, mid, qL, qR);
res = res + query(2 * idx + 1, mid + 1, high, qL, qR);
return res;
}
void build(int arr[])
{
build(1, 1, n, arr);
}
int query(int l, int r)
{
return query(1, 1, n, l, r).ans;
}
};
SegmentTree tree;
void solve()
{
std::cin >> n >> s;
for(int i = 1 ; i <= n ; ++i)
{
a[i] = (s[i - 1] == 'T' ? 1 : -1);
}
tree.build(a);
std::cin >> m;
for(int i = 1 ; i <= m ; ++i)
{
int l, r;
std::cin >> l >> r;
std::cout << tree.query(l, r) << "\n";
}
}
void fastIO()
{
std::ios_base::sync_with_stdio(false);
std::cin.tie(NULL);
std::cout.tie(NULL);
}
signed main()
{
fastIO();
solve();
}
