import sys



readline = sys.stdin.readline

MOD = 10 ** 9 + 7

INF = float('INF')

sys.setrecursionlimit(10 ** 5)





def main():

    s, w = list(map(int, readline().split()))



    if w >= s:

        print("unsafe")

    else:

        print("safe")





if __name__ == '__main__':

    main()

s, w = list(map(int, input().split()))



if w >= s:

    print("unsafe")

else:

    print("safe")
import sys

readline = sys.stdin.readline
MOD = 10**9 + 7
INF = float("INF")
sys.setrecursionlimit(10**5)


def main():
    s, w = list(map(int, readline().split()))
    if w >= s:
        print("unsafe")
    else:
        print("safe")


if __name__ == "__main__":
    main()

s, w = list(map(int, input().split()))
if w >= s:
    print("unsafe")
else:
    print("safe")

-import sys - -readline = sys.stdin.readline -MOD = 10**9 + 7 -INF = float("INF") -sys.setrecursionlimit(10**5) - - -def main(): -    s, w = list(map(int, readline().split())) -    if w >= s: -        print("unsafe") -    else: -        print("safe") - - -if __name__ == "__main__": -    main() +s, w = list(map(int, input().split())) +if w >= s: +    print("unsafe") +else: +    print("safe")