#include <iostream>
#include <vector>

using namespace std;

int main() {
  int n, i;
  cin >> n;
  vector<int> v(n);

  for (i=0; i<n; i++){
    cin >> v[i];
  }

  for (i=0; i<n-1; i++){
    if (v[0]==0 || abs(v[i]-v[i+1])!=1){
      cout << 'F' << endl;
      return 0;
    }
  }

  cout << 'T' << endl;
  return 0;
}