A = list(map(int, input().split()))
del A[0]
flag = "T"

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