import java.util.Scanner;
public class Main
{
 	public static void main(String[] args)
    {
     	 Scanner sc = new Scanner(System.in);
      	String[] num = sc.nextLine().split(" ");
      	if(Integer.parseInt(num[0]) > Integer.parseInt(num[1]))
        {
         	System.out.println("safe"); 
        }else{
          	System.out.println("unsafe"); 
        }
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz