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

int main(){
    int T,in,x=0;
    cin >> T;
    while(cin >> in){
        if(x-in!=1&&x-in!=-1){
            cout << 'F' << endl;
            return 0;
        }
        x=in;
    }
    cout << 'T' << endl;

    return 0;
}