#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18;
const int MOD = 1e9 + 7;
struct mi {
int v;
explicit operator int() const { return v; }
mi() { v = 0; }
mi(long long _v) : v(_v % MOD) { v += (v < 0) * MOD; }
};
mi &operator+=(mi &a, mi b) {
if ((a.v += b.v) >= MOD) a.v -= MOD;
return a;
}
mi &operator-=(mi &a, mi b) {
if ((a.v -= b.v) < 0) a.v += MOD;
return a;
}
mi operator+(mi a, mi b) { return a += b; }
mi operator-(mi a, mi b) { return a -= b; }
mi operator*(mi a, mi b) { return mi((long long)a.v * b.v); }
mi &operator*=(mi &a, mi b) { return a = a * b; }
mi pow(mi a, long long p) {
assert(p >= 0);
return p == 0 ? 1 : pow(a * a, p / 2) * (p & 1 ? a : 1);
}
mi inv(mi a) {
assert(a.v != 0);
return pow(a, MOD - 2);
}
mi operator/(mi a, mi b) { return a * inv(b); }
template <class T>
void print(vector<T>& arr, bool __endl = true){
for (int i = 0; i < arr.size(); i ++) cout << arr[i] << ' ';
if (__endl)
cout << '\n';
}
template <class T>
void input(vector<T>& arr){
for (int i = 0; i < arr.size(); i ++) cin >> arr[i];
}
struct SegTreeNode{
int L = 0, R = 0, S = 0, A = 0;
SegTreeNode(){}
SegTreeNode(int a, int b, int c, int d) : L(a), R(b), S(c), A(d) {}
void combine(SegTreeNode u, SegTreeNode v){
L = max(u.L, u.S + v.L);
R = max(u.R + v.S, v.R);
S = u.S + v.S;
A = max(max(u.A + v.S, u.S + v.A), u.L + v.R);
}
};
struct SegTree{
vector<SegTreeNode> tree;
int n;
SegTree(int N, string& s){
n = N;
tree.resize(4 * n);
build(0, 0, n - 1, s);
}
void build(int v, int l, int r, string& s){
if (l == r){
if (s[l] == 'T') tree[v] = SegTreeNode(1, 1, 1, 1);
else tree[v] = SegTreeNode(0, 0, -1, 0);
return;
}
int m = (l + r) / 2;
build(2 * v + 1, l, m, s);
build(2 * v + 2, m + 1, r, s);
tree[v].combine(tree[2 * v + 1], tree[2 * v + 2]);
}
SegTreeNode query(int v, int tl, int tr, int l, int r){
if (tl == l && tr == r) return tree[v];
int m = (tl + tr) / 2;
if (r <= m) return query(2 * v + 1, tl, m, l, r);
if (l > m) return query(2 * v + 2, m + 1, tr, l, r);
SegTreeNode ret;
ret.combine(query(2 * v + 1, tl, m, l, m), query(2 * v + 2, m + 1, tr, m + 1, r));
return ret;
}
};
// #define with_testcases
void t_main(signed __T){
int n;
cin >> n;
string s;
cin >> s;
SegTree sg(n, s);
int q;
cin >> q;
while (q --){
int l, r;
cin >> l >> r;
--l; -- r;
cout << sg.query(0, 0, n - 1, l, r).A << '\n';
}
}
signed main(){
cin.tie(nullptr) -> sync_with_stdio(false);
int t = 1;
#ifdef with_testcases
cin >> t;
#endif
for (int i = 1; i <= t; i ++) {
t_main(i);
// cout << '\n';
}
}
