#include <bits/stdc++.h>
using namespace std;
#define int long long
#define eb emplace_back
#define mp make_pair
#define pb push_back
#define pp pop_back
#define endl '\n'
#define ff first
#define ss second
#define stop exit(0)
#define sz(x) (int)x.size()
#define pause system("pause")
#define all(x) (x).begin(), (x).end()
#define deb(x) cout << #x << "-" << x << endl
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef string str;
typedef long long ll;
typedef vector<int> vii;
typedef pair<int, int> pii;
const long long INF = LLONG_MAX;
const int inf = INT_MAX;
const int mod = 998244353;
const int MOD = 1000000007;
const int dx[] = {-1,0,1,0};
const int dy[] = {0,1,0,-1};
const double PI = 2 * acos(0.0);
const int N = 2e5+5;
int n;
map <int, int> id;
set<int> s;
int a[N];
int t[N*4],t1[N*4];
int pref[N],suf[N];
void update(int node, int l, int r, int pos, int val) {
if (pos < l || pos > r) return;
if (l == r) {
t[node] = val;
return;
}
int mid = (l+r)/2;
update(node*2,l,mid,pos,val);
update(node*2+1,mid+1,r,pos,val);
t[node] = max(t[node*2],t[node*2+1]);
}
int getans(int node, int l, int r, int L, int R) {
if (r < L || l > R) return -inf;
if (l >= L && r <= R) return t[node];
int mid = (l+r)/2;
return max(getans(node*2,l,mid,L,R), getans(node*2+1,mid+1,r,L,R));
}
void update1(int node, int l, int r, int pos, int val) {
if (pos < l || pos > r) return;
if (l == r) {
t1[node] = val;
return;
}
int mid = (l+r)/2;
update1(node*2,l,mid,pos,val);
update1(node*2+1,mid+1,r,pos,val);
t1[node] = max(t1[node*2],t1[node*2+1]);
}
int getans1(int node, int l, int r, int L, int R) {
if (r < L || l > R) return -inf;
if (l >= L && r <= R) return t1[node];
int mid = (l+r)/2;
return max(getans1(node*2,l,mid,L,R), getans1(node*2+1,mid+1,r,L,R));
}
inline void test_case() {
cin >> n;
string c;cin >> c;
for (int i = 0; i < n; i++) {
if (c[i] == 'T') a[i+1] = 1; else a[i+1] = -1;
}
pref[0] = suf[n+1] = 0;
for (int i = 1; i <= n; i++) {
pref[i] = pref[i-1] + a[i];
update(1,1,n,i,pref[i]);
}
for (int i = n; i >= 1; i--) {
suf[i] = suf[i+1] + a[i];
update1(1,1,n,i,suf[i]);
}
int q;
cin >> q;
while (q--) {
int l; int r;
cin >> l >> r;
int val = getans(1,1,n,l,r);
val -= pref[l-1];
int val2 = getans1(1,1,n,l,r)-suf[r+1];
cout << max(val,val2) << endl;
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int T = 1;
// cin >> T;
while (T--) test_case();
return 0;
}
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