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

int main(){
	cin.tie(0),ios::sync_with_stdio(false);
	int t; cin>>t;
	bool yes=true;
	{
		int p; cin>>p;
		if(p==0)yes=false;
		for(int i=1;i<t;++i){
			int x; cin>>x;
			if(abs(x-p)!=1)yes=false;
			p=x;
		}
	}
	cout<<(yes?"T"s:"F"s)<<"\n"s;
}