import java.util.*;

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

        int s = scan.nextInt(), w = scan.nextInt();

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

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

        int s = scan.nextInt(), w = scan.nextInt();

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

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

        int s = scan.nextInt(), w = scan.nextInt();

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

        scan.close();
        return;
    } main {
        Scanner scan = new Scanner(System.in);

        int s = scan.nextInt(), w = scan.nextInt();

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

        scan.close();
        return;
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int s = scan.nextInt() s scan.nextInt() scan.nextInt scan w = scan.nextInt(); w scan.nextInt() scan.nextInt scan 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" scan.close() scan.close scan return; String[] args args public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        int s = scan.nextInt(), w = scan.nextInt();

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

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

        int s = scan.nextInt(), w = scan.nextInt();

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

        scan.close();
        return;
    }
} Main
import java.util.*;

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

        int s = scan.nextInt(), w = scan.nextInt();

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

        scan.close();
        return;
    }
}