import java.util.*;
import java.io.*;

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

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