import java.util.*;

public class Main {
  public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  }

  int s;
  int w;
  String ans;

  public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  }
  
  void solve() {
    ans = s <= w ? "unsafe" : "safe";
  }

  void show() {
    System.out.println(ans);
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  }

  int s;
  int w;
  String ans;

  public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  }
  
  void solve() {
    ans = s <= w ? "unsafe" : "safe";
  }

  void show() {
    System.out.println(ans);
  }
} Main int s; s int w; w String ans; ans public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  } main {
    Main main = new Main();
    main.solve();
    main.show();
  } Main main = new Main(); main new Main() main.solve() main.solve main main.show() main.show main String[] args args public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  } Main {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    } {
      sc.close();
    } sc.close() sc.close sc {
      s = sc.nextInt();
      w = sc.nextInt();
    } s = sc.nextInt() s sc.nextInt() sc.nextInt sc w = sc.nextInt() w sc.nextInt() sc.nextInt sc void solve() {
    ans = s <= w ? "unsafe" : "safe";
  } solve {
    ans = s <= w ? "unsafe" : "safe";
  } ans = s <= w ? "unsafe" : "safe" ans s <= w ? "unsafe" : "safe" s <= w s w "unsafe" "safe" void show() {
    System.out.println(ans);
  } show {
    System.out.println(ans);
  } System.out.println(ans) System.out.println System.out System System.out ans public class Main {
  public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  }

  int s;
  int w;
  String ans;

  public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  }
  
  void solve() {
    ans = s <= w ? "unsafe" : "safe";
  }

  void show() {
    System.out.println(ans);
  }
} public class Main {
  public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  }

  int s;
  int w;
  String ans;

  public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  }
  
  void solve() {
    ans = s <= w ? "unsafe" : "safe";
  }

  void show() {
    System.out.println(ans);
  }
} Main
import java.util.*;

public class Main {
  public static void main(String[] args) {
    Main main = new Main();
    main.solve();
    main.show();
  }

  int s;
  int w;
  String ans;

  public Main() {
    Scanner sc = new Scanner(System.in);
    try {
      s = sc.nextInt();
      w = sc.nextInt();
    } finally {
      sc.close();
    }
  }
  
  void solve() {
    ans = s <= w ? "unsafe" : "safe";
  }

  void show() {
    System.out.println(ans);
  }
}
