import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    }
} Main public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    } main {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    } BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter pw=new PrintWriter(System.out); pw new PrintWriter(System.out) String str[]=br.readLine().split(" "); str br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int s=Integer.parseInt(str[0]); s Integer.parseInt(str[0]) Integer.parseInt Integer str[0] str 0 int w=Integer.parseInt(str[1]); w Integer.parseInt(str[1]) Integer.parseInt Integer str[1] str 1 if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe"); s<=w s w pw.println("unsafe") pw.println pw "unsafe" pw.println("safe") pw.println pw "safe" pw.flush() pw.flush pw pw.close() pw.close pw String args[] args public class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    }
} public class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    }
} Main
import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        String str[]=br.readLine().split(" ");
        int s=Integer.parseInt(str[0]);
        int w=Integer.parseInt(str[1]);
        if(s<=w)
        pw.println("unsafe");
        else
        pw.println("safe");
        pw.flush();
        pw.close();
    }
}