

def main():

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

    if s <= w:

        print("unsafe")

    else:

        print("safe")



if __name__ == '__main__':

    main()

def main():

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

    answer = "unsafe" if w >= s else "safe"

    print(answer)

if __name__ == '__main__':

    main()

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


if __name__ == "__main__":
    main()

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


if __name__ == "__main__":
    main()

-    if s <= w: -        print("unsafe") -    else: -        print("safe") +    answer = "unsafe" if w >= s else "safe" +    print(answer)