#cording:utf-8



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

if S<=W:

  print("unsafe")



else:

  print("safe")

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

if s<=w:

    print("unsafe")

else:

    print("safe")

# cording:utf-8
S, W = list(map(int, input().split()))
if S <= W:
    print("unsafe")
else:
    print("safe")

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

-# cording:utf-8 -S, W = list(map(int, input().split())) -if S <= W: +s, w = list(map(int, input().split())) +if s <= w: