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();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 
} 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();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 
} Main public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int S = sc.nextInt();
      	int W = sc.nextInt();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } main {
        Scanner sc= new Scanner(System.in);
        int S = sc.nextInt();
      	int W = sc.nextInt();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 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 boolean isSafe = S > W; isSafe S > W S W String ans = "unsafe"; ans "unsafe" if (isSafe) ans = "safe"; isSafe ans = "safe" ans "safe" System.out.println(ans) System.out.println System.out System System.out ans 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();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 
} public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int S = sc.nextInt();
      	int W = sc.nextInt();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 
} 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();
        boolean isSafe = S > W;
      String ans = "unsafe";  
      if (isSafe) ans = "safe";
      	System.out.println(ans);
    } 
}