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



if w >= s:

    print('unsafe')

else:

    print('safe')

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

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

s, w = list(map(int, input().split()))
print(("un" * (w >= s) + "safe"))

-if w >= s: -    print("unsafe") -else: -    print("safe") +print(("un" * (w >= s) + "safe"))