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: Accepted)

#include <stdio.h>  /*入出力*/
#include <stdlib.h> /*標準ライブラリ*/
#include <string.h> /*文字列*/
#include <math.h>   /*計算*/
#include <assert.h> /*確認*/
#include <ctype.h>  /*文字操作*/
#include <stdbool.h>/*bool型*/
#include <limits.h>/*限界*/
//---------------------------------------------------
#define rep(i, n) for(int  i = 0; i < (n); i++)
#define ABS(a) (((a)>(0))?a:-(a))
#define LL long long
#define MOD 1000000007//10^9+7(素数)
//---------------------------------------------------
LL max(LL a, LL b)
{
  if (a<b) {
    a = b;
  }
  return a;
}

void swap(int *a, int *b)
{
  int temp;
  temp = *a;*a = *b;*b = temp;
}
//-------------------------------------------------------
int main(void)
{
  int n;
  int u;
  scanf("%d %d", &n, &u);
  if (n > u) {
    printf("safe\n");
  }else{
    printf("unsafe\n" );
  }
  return 0;
}