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

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

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