/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */


import java.util.*;

/**
 *
 * @author Admin
 */
public class Main {
    
    
    public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    }
    
    
} import java.util.*; util.* java public class Main {
    
    
    public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    }
    
    
} Main public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    } main {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    } Scanner s=new Scanner(System.in); s new Scanner(System.in) int ss=s.nextInt(); ss s.nextInt() s.nextInt s int w=s.nextInt(); w s.nextInt() s.nextInt s if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe"); ss>w ss w System.out.println("safe") System.out.println System.out System System.out "safe" System.out.println("unsafe") System.out.println System.out System System.out "unsafe" String args[] args public class Main {
    
    
    public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    }
    
    
} public class Main {
    
    
    public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    }
    
    
} Main
/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */


import java.util.*;

/**
 *
 * @author Admin
 */
public class Main {
    
    
    public static void main(String args[])
    {
    Scanner s=new Scanner(System.in);
    
    int ss=s.nextInt();
    
    int w=s.nextInt();
    
    if(ss>w)
        System.out.println("safe");
    else
    System.out.println("unsafe");
   
         
    
    
    
    }
    
    
}
