import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int n = sc.nextInt();
		int[] ints = new int[n];
		for (int i=0; i<n; i++) {
			ints[i] = sc.nextInt();
		}
		if (ints[0]==0 || ints[0] > 1 || ints[0] < -1) {System.out.println("F");}
		else {
			boolean possible = true;
			for (int i=0; i<n-1; i++) {
				int temp = Math.abs(ints[i+1]-ints[i]);
				if (temp > 1 || temp==0) {possible = false; break;}
			}
			System.out.println(possible==true?"T":"F");
		}
	}
}