#!/usr/bin/env python3

import sys, math, itertools, collections, bisect

input = lambda: sys.stdin.buffer.readline().rstrip().decode('utf-8')

inf = float('inf') ;mod = 10**9+7

mans = inf ;ans = 0 ;count = 0 ;pro = 1



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

if s <= w:

  print("unsafe")

else:

  print("safe")
#!/usr/bin/env python3

import sys, math, itertools, collections, bisect

input = lambda: sys.stdin.buffer.readline().rstrip().decode('utf-8')

inf = float('inf') ;mod = 10**9+7

mans = inf ;ans = 0 ;count = 0 ;pro = 1



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

print(("unsafe" if s <= w else "safe"))
#!/usr/bin/env python3
import sys, math, itertools, collections, bisect

input = lambda: sys.stdin.buffer.readline().rstrip().decode("utf-8")
inf = float("inf")
mod = 10**9 + 7
mans = inf
ans = 0
count = 0
pro = 1
s, w = list(map(int, input().split()))
if s <= w:
    print("unsafe")
else:
    print("safe")

#!/usr/bin/env python3
import sys, math, itertools, collections, bisect

input = lambda: sys.stdin.buffer.readline().rstrip().decode("utf-8")
inf = float("inf")
mod = 10**9 + 7
mans = inf
ans = 0
count = 0
pro = 1
s, w = list(map(int, input().split()))
print(("unsafe" if s <= w else "safe"))

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