S, W = list(map(int,input().split()))

if S <= W:

    print("unsafe")

else:

    print("safe")

import sys

def input():

    return sys.stdin.readline()[:-1]

def main():

#    N = int(input())

    S, W = list(map(int,input().split()))

#    S = input()

    print(("safe" if S > W else "unsafe"))

if __name__ == '__main__':

    main()

S, W = list(map(int, input().split()))
if S <= W:
    print("unsafe")
else:
    print("safe")

import sys


def input():
    return sys.stdin.readline()[:-1]


def main():
    #    N = int(input())
    S, W = list(map(int, input().split()))
    #    S = input()
    print(("safe" if S > W else "unsafe"))


if __name__ == "__main__":
    main()

-S, W = list(map(int, input().split())) -if S <= W: -    print("unsafe") -else: -    print("safe") +import sys + + +def input(): +    return sys.stdin.readline()[:-1] + + +def main(): +    #    N = int(input()) +    S, W = list(map(int, input().split())) +    #    S = input() +    print(("safe" if S > W else "unsafe")) + + +if __name__ == "__main__": +    main()