import java.util.*;
import java.util.HashSet;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
import java.util.Scanner;


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

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

    }
}



 import java.util.*; util.* java import java.util.HashSet; HashSet java.util import java.util.Map; Map java.util import java.util.HashMap; HashMap java.util import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

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

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

    } main {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();

        if (w - s >= 0){
            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 >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        } w - s >= 0 w - s w s 0 {
            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) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int w = sc.nextInt();

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

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

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

    }
} Main
import java.util.*;
import java.util.HashSet;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;
import java.util.Scanner;


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

        if (w - s >= 0){
            System.out.println("unsafe");
        } else {
            System.out.println("safe");
        }

    }
}




