def main():

    ans = 'safe'

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

    if w >= s:

        ans = 'unsafe'

    

    print(ans)



if __name__ == '__main__':

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

if s <= w:

  print('unsafe')

else:

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


if __name__ == "__main__":
    main()

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

-def main(): -    ans = "safe" -    s, w = list(map(int, input().split())) -    if w >= s: -        ans = "unsafe" -    print(ans) - - -if __name__ == "__main__": -    main() +s, w = list(map(int, input().split())) +if s <= w: +    print("unsafe") +else: +    print("safe")