import java.util.*;

public class Main {
	public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} import java.util.*; util.* java public class Main {
	public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } main {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } final Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a a b; b a = sc.nextInt() a sc.nextInt() sc.nextInt sc b = sc.nextInt() b sc.nextInt() sc.nextInt sc if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        } a<=b a b {
            System.out.println("unsafe");
        } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
            System.out.println("safe");
        } System.out.println("safe") System.out.println System.out System System.out "safe" final String[] args args public class Main {
	public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} public class Main {
	public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main
import java.util.*;

public class Main {
	public static void main(final String[] args) {
        final Scanner sc = new Scanner(System.in);

        int a, b;
        a = sc.nextInt(); // 羊
        b = sc.nextInt(); // 狼
        if(a<=b){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
}