import java.io.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    }
} import java.io.*; io.* java public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    }
} Main public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    } main {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    } BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in)); reader new BufferedReader (new InputStreamReader (System.in)) String[] arr = reader.readLine().split (" "); arr reader.readLine().split (" ") reader.readLine().split reader.readLine() reader.readLine reader " " int S S W; W S = Integer.parseInt (arr[0]) S Integer.parseInt (arr[0]) Integer.parseInt Integer arr[0] arr 0 W = Integer.parseInt (arr[1]) W Integer.parseInt (arr[1]) Integer.parseInt Integer arr[1] arr 1 System.out.println (S <= W ? "unsafe" : "safe") System.out.println System.out System System.out S <= W ? "unsafe" : "safe" S <= W S W "unsafe" "safe" return; String[] args args public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    }
} public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    }
} Main
import java.io.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        String[] arr = reader.readLine().split (" ");
        int S, W;
        S = Integer.parseInt (arr[0]);
        W = Integer.parseInt (arr[1]);
        System.out.println (S <= W ? "unsafe" : "safe");
        return;
    }
}