import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    }

} import java.io.FileNotFoundException; FileNotFoundException java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    }

} Main public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    } main {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    } 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 if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	} W>=S W S {
    		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" String[] args args public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    }

} public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    }

} Main
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws FileNotFoundException {

//    	File file = new File("src/in.txt");

        //コード
//    	Scanner sc = new Scanner(file);
    	Scanner sc = new Scanner(System.in);

    	int S = sc.nextInt();
    	int W = sc.nextInt();

    	if(W>=S) {
    		System.out.println("unsafe");
    	} else {
    		System.out.println("safe");
    	}

    }

}