import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    } main {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    } Scanner sn = new Scanner(System.in); sn new Scanner(System.in) int s = sn.nextInt(); s sn.nextInt() sn.nextInt sn int w = sn.nextInt(); w sn.nextInt() sn.nextInt sn if(s <= w) {
            System.out.print("unsafe");
            return;
        } s <= w s w {
            System.out.print("unsafe");
            return;
        } System.out.print("unsafe") System.out.print System.out System System.out "unsafe" return; System.out.print("safe") System.out.print System.out System System.out "safe" String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sn = new Scanner(System.in);
        
        int s = sn.nextInt();
        int w = sn.nextInt();
        
        if(s <= w) {
            System.out.print("unsafe");
            return;
        }
        
        System.out.print("safe");
    }
}
