import bisect

import cmath

import heapq

import itertools

import math

import operator

import os

import random

import re

import string

import sys

from collections import Counter, defaultdict, deque

from copy import deepcopy

from decimal import Decimal

from functools import lru_cache, reduce

from math import gcd

from operator import add, itemgetter, mul, xor



import numpy as np



if os.getenv("LOCAL"):

    sys.stdin = open("_in.txt", "r")



sys.setrecursionlimit(10 ** 9)

INF = float("inf")

IINF = 10 ** 18

MOD = 10 ** 9 + 7

# MOD = 998244353



S, W = list(map(int, sys.stdin.buffer.readline().split()))

if S <= W:

    print('unsafe')

else:

    print('safe')



import os



import sys



if os.getenv("LOCAL"):

    sys.stdin = open("_in.txt", "r")



sys.setrecursionlimit(10 ** 9)

INF = float("inf")

IINF = 10 ** 18

MOD = 10 ** 9 + 7

# MOD = 998244353



S, W = list(map(int, sys.stdin.buffer.readline().split()))

if S <= W:

    print('unsafe')

else:

    print('safe')

import bisect
import cmath
import heapq
import itertools
import math
import operator
import os
import random
import re
import string
import sys
from collections import Counter, defaultdict, deque
from copy import deepcopy
from decimal import Decimal
from functools import lru_cache, reduce
from math import gcd
from operator import add, itemgetter, mul, xor
import numpy as np

if os.getenv("LOCAL"):
    sys.stdin = open("_in.txt", "r")
sys.setrecursionlimit(10**9)
INF = float("inf")
IINF = 10**18
MOD = 10**9 + 7
# MOD = 998244353
S, W = list(map(int, sys.stdin.buffer.readline().split()))
if S <= W:
    print("unsafe")
else:
    print("safe")

import os
import sys

if os.getenv("LOCAL"):
    sys.stdin = open("_in.txt", "r")
sys.setrecursionlimit(10**9)
INF = float("inf")
IINF = 10**18
MOD = 10**9 + 7
# MOD = 998244353
S, W = list(map(int, sys.stdin.buffer.readline().split()))
if S <= W:
    print("unsafe")
else:
    print("safe")

-import bisect -import cmath -import heapq -import itertools -import math -import operator -import random -import re -import string -from collections import Counter, defaultdict, deque -from copy import deepcopy -from decimal import Decimal -from functools import lru_cache, reduce -from math import gcd -from operator import add, itemgetter, mul, xor -import numpy as np