#include<iostream>

using namespace std;

int main(){
  int n,tmp=0,p;
  cin >> n ;
  int a[n];
  for(int i=0; i<n; i++){
    cin >> a[i];
  }
  for(int i=0; i<n; i++){
    p = a[i];
    if(abs(p-tmp)!=1){
      cout << "F" << endl;
      return 0;
    }
    tmp = p;
  }
  cout << "T" << endl;
  return 0;
}