import sys,collections
sys.setrecursionlimit(10**7)
def Is(): return [int(x) for x in sys.stdin.readline().split()]
def Ss(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

t = I()
p = 0
ans = "T"
for i in range(t):
    x = I()
    if abs(x - p) != 1:
        ans = "F"
        break
    p = x
print(ans)