#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)s; i < (int)e; ++i)
#define all(a) (a).begin(), (a).end()

int main() {
    cin.tie(nullptr);
    
    int T;
    cin >> T;
    
    int now = 0;
    char ans = 'T';
    rep(i, 0, T) {
        int X;
        cin >> X;
        
        if (abs(now - X) != 1) ans = 'F';
        now = X;
    }
    
    cout << ans << '\n';
}