/*package whatever //do not write package name here */

import java.io.*;
import java.util.*;
public class Main {
    
	public static void main (String[] args) {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	}
}
		
		
		    import java.io.*; io.* java import java.util.*; util.* java public class Main {
    
	public static void main (String[] args) {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	}
} Main public static void main (String[] args) {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	} main {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	} Scanner s=new Scanner(System.in); s new Scanner(System.in) long m=s.nextLong(); m s.nextLong() s.nextLong s long n=s.nextLong(); n s.nextLong() s.nextLong s if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe"); n>=m n m 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 s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	}
} public class Main {
    
	public static void main (String[] args) {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	}
} Main
/*package whatever //do not write package name here */

import java.io.*;
import java.util.*;
public class Main {
    
	public static void main (String[] args) {
		Scanner s=new Scanner(System.in);
		long m=s.nextLong();
		long n=s.nextLong();
		if(n>=m)
		System.out.println("unsafe");
		else
		System.out.println("safe");
		
	}
}
		
		
		   