#include<bits/stdc++.h>
using namespace std;
using Int = long long;
signed main(){
  Int n;
  cin>>n;
  vector<Int> v(n+1,0);
  for(Int i=0;i<n;i++) cin>>v[i+1];
  for(Int i=0;i<n;i++){
    if(abs(v[i]-v[i+1])!=1){
      cout<<"F"<<endl;
      return 0;
    }
  }
  cout<<"T"<<endl;
  return 0;
}