#include <bits/stdc++.h>
using namespace std;

int main()
{
    int t;
    cin >> t;
    bool flag = true;
    vector<int> x(101);
    for(int i = 0; i < t; i++){
        cin >> x[i];
        if(i == 0 && x[i] == 0) flag = false;
        if(i > 1 && abs(x[i] - x[i-1]) != 1) flag = false;
    }

    cout << (flag ? 'T' : 'F') << endl;

    return 0;
}