#include <iostream>
using namespace std;
int main(){
int Num,x,before=0;
cin>>Num;
int* point=new int[Num];
for (x=0;x<Num;x++){
	cin>>point[x];
}

for (x=0;x<Num;x++){
	if((point[x]-before==1)||(point[x]-before==-1)){
		before=point[x];
	}else{
		x=-1;
		break;
	}
}
if(x==-1){
	cout<<"F"<<endl;
}else{
	cout<<"T"<<endl;
}
return 0;
}