import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

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

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int s = sc.nextInt();
        int w = sc.nextInt();
        if (w >= s) {
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }
    }
}
