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