import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

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

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

