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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int	main(void)
{
	int taka_hp, taka_of, aoki_hp, aoki_of;
	scanf("%d %d %d %d", &taka_hp, &taka_of, &aoki_hp, &aoki_of);

	while (taka_hp >= 0 && aoki_hp >= 0)
	{
		taka_hp = taka_hp - aoki_of;
		aoki_hp = aoki_hp - taka_of;
	}
	if (taka_hp <= 0)
		printf("No\n");
	else
		printf("Yes\n");

	return (0);
}