#include <bits/stdc++.h>
using namespace std;
int main(){
int n,k[105];
cin>>n;
for(int i=0;i<n;++i){
  cin>>k[i];
if(i==0&&k[i]!=1&&k[i]!=-1) {
  cout<<"F"<<endl;
return 0;
}
if(i&&abs(k[i]-k[i-1])!=1){
  cout<<"F"<<endl;
return 0;
}
}
cout<<"T"<<endl;
}