import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int t = in.nextInt();

        String ans = "T";
        int[] x = new int[t];

        for(int i=0; i<t; i++) {
            x[i] = in.nextInt();
        }

        if(t == 1 && (x[0] != 1 || x[0] != -1)) ans = "F";
        if(x[0] == 0) ans = "F";
        for(int i=1; i<t; i++) {
            if(Math.abs(x[i-1] - x[i]) > 1 || x[i-1] == x[i]) {
                ans = "F";
                break;
            }
        }

        System.out.println(ans);
    }
}