import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  }
} import java.util.Scanner; Scanner java.util public class Main{
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  }
} Main public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  } main {
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    } s <= w s w {
      System.out.print("unsafe");
    } System.out.print("unsafe") System.out.print System.out System System.out "unsafe" {
      System.out.print("safe");
    } System.out.print("safe") System.out.print System.out System System.out "safe" String[] args args public class Main{
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  }
} public class Main{
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  }
} Main
import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int s = sc.nextInt();
    int w = sc.nextInt();
    
    if(s <= w){
      System.out.print("unsafe");
    }else{
      System.out.print("safe");
    }
    
  }
}