import sys read = sys.stdin.buffer.read readline = sys.stdin.buffer.readline readlines = sys.stdin.buffer.readlines T,*X = map(int,read().split()) X = [0] + X dx = [y - x for x,y in zip(X,X[1:])] answer = 'T' if all(x == 1 for x in dx) else 'F' print(answer)