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