#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main() {
    int t;
    cin >> t;
    int x1 = 0;
    int x2;
    bool ans = true;
    for(int i = 0;i < t;i++){
        cin >> x2;
        if(x1+1 != x2 && x1-1 != x2)ans = false;
        x1 = x2;
    }
    if(ans)cout << 'T';
    else cout << 'F';
    return 0;
}