import sys

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(10 ** 7)



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

if w >= s:

    print('unsafe')

else:

    print('safe')

import sys

read = sys.stdin.buffer.read

readline = sys.stdin.buffer.readline

readlines = sys.stdin.buffer.readlines

sys.setrecursionlimit(10 ** 7)



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

if w >= s:

    print('unsafe')

else:

    print('safe')

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10**7)
s, w = list(map(int, readline().split()))
if w >= s:
    print("unsafe")
else:
    print("safe")

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10**7)
s, w = list(map(int, read().split()))
if w >= s:
    print("unsafe")
else:
    print("safe")

-s, w = list(map(int, readline().split())) +s, w = list(map(int, read().split()))