#include<stdio.h>

int main(){
  int s,w;
  scanf("%d %d",&s,&w);

  if( ((s*100)/2)*100 > w ){
    printf("%d",s/2);
    printf("safe\n");
  }else if( ((s*100)/2)*100 <= w){
    printf("%d",s/2);
    printf("unsafe\n");
  }

}