import sys


list = int(input())
del list[0]
flag = "T"

if list[0] == 1 or list[0] == -1:
    for i in range(len(list) - 1):
        if list[i] + 1 == list[i + 1] or list[i] - 1 == list[i + 1]:
            flag = "T"
        else:
            flag = "F"
            break
    print(flag)
else:
    flag = "F"
    print(flag)