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)

N=[int(x) for x in input().split()]
if not N[2]%N[1]==0:
   c=N[2]//N[1]+1
else:
    c=N[2]//N[1]
if not N[0]%N[3]==0:
   c=N[0]//N[3]+1

   d=N[0]//N[3]+1
else:
    d=N[0]//N[3]
if d>=c:
    print("Yes")
else:
    print("No")