import java.util.*;

class Main{
    static int mod = 1000000000+7;
    public static void main(String args[]) {
        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.util.*; util.* java class Main{
    static int mod = 1000000000+7;
    public static void main(String args[]) {
        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 static int mod = 1000000000+7; mod 1000000000+7 1000000000 7 public static void main(String args[]) {
        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 {
        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
import java.util.*;

class Main{
    static int mod = 1000000000+7;
    public static void main(String args[]) {
        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");
        }
        
    }
}
