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.

Examples

Input

4 5

Output

unsafe

Input

100 2

Output

safe

Input

10 10

Output

unsafe

见题面

见题面