Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in Python (3.8.2) (judge verdict: Runtime Error)

cnt=0
S=str(input())
mc=[0]*2019
L=len(S)

tg=0
digit=1
for s in S[::-1]:
    tg+=int(s)*digit
    mt=tg%2019
    if mt==0:cnt+=1
    cnt+=mc[mt]
    mc[mt]+=1
    digit*=10
    
print(cnt)