#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <climits>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
typedef long long ll;
int main(){
    ll n;
    cin >> n;
    vector<ll> a(n + 1);
    for(int i = 1;i < n + 1;i++)cin >> a[i];
    a[0] = 0;
    for(int i = 1;i < n + 1;i++){
        if(abs(a[i] - a[i - 1]) != 1){
            cout << "F" << endl;
            return 0;
        }
    }
    cout << "T" << endl;
}