using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;
using System.Text;

public class Program
{

    public void Proc()
    {
        int stepCount = int.Parse(Reader.ReadLine());

        int current = 0;

        bool isValid = true;
        for (int i = 0; i < stepCount; i++) {
            int pos = int.Parse(Reader.ReadLine());
            if(Math.Abs(pos-current)!=1) {
                isValid = false;
            }
            current = pos;
        }
        Console.WriteLine(isValid?"T":"F");
    
    
    }



    public class Reader
    {
        private static StringReader sr;
        public static bool IsDebug = false;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (sr == null)
                {
                    sr = new StringReader(InputText.Trim());
                }
                return sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        private static string InputText = @"



3
1
2
1


";
    }

    public static void Main(string[] args)
    {
#if DEBUG
        Reader.IsDebug = true;
#endif
        Program prg = new Program();
        prg.Proc();
    }
}