import java.util.*;
import java.util.TreeMap;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Collections;
 
class Main{
    public static void main(String[] args){
        
        Scanner sc = new Scanner(System.in);
 
        int S = sc.nextInt();
        int W = sc.nextInt();
 
        if(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        }
    }
} import java.util.*; util.* java import java.util.TreeMap; TreeMap 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.Collections; Collections java.util class Main{
    public static void main(String[] args){
        
        Scanner sc = new Scanner(System.in);
 
        int S = sc.nextInt();
        int W = sc.nextInt();
 
        if(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        }
    }
} Main public static void main(String[] args){
        
        Scanner sc = new Scanner(System.in);
 
        int S = sc.nextInt();
        int W = sc.nextInt();
 
        if(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        }
    } main {
        
        Scanner sc = new Scanner(System.in);
 
        int S = sc.nextInt();
        int W = sc.nextInt();
 
        if(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        }
    } 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(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        } S>W S W {
            System.out.println("safe");
        } System.out.println("safe") System.out.println System.out System System.out "safe" {
            System.out.println("unsafe");
        } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" String[] args args
import java.util.*;
import java.util.TreeMap;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Collections;
 
class Main{
    public static void main(String[] args){
        
        Scanner sc = new Scanner(System.in);
 
        int S = sc.nextInt();
        int W = sc.nextInt();
 
        if(S>W){
            System.out.println("safe");
        }
        else{
            System.out.println("unsafe");
        }
    }
}