import java.util.*;


public class Main {
    public static void main(String[] args) 
    {
        Scanner sc=new Scanner(System.in);
        int sheep=sc.nextInt(); //羊の数
        int wolves=sc.nextInt(); //狼の数
        
            if(sheep>wolves)
            {
                System.out.println("safe"); //襲われない
            }
            else
            {
                System.out.println("unsafe"); //襲われる
            }
        
    }
}




/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