import java.io.File;
import java.io.FileWriter;
import java.io.Writer;
import java.util.Scanner;

public class RemoveSameLines {
  public static void main(String[] args) {
    if (args.length < 2) {
      System.out.println("IN_FILE OUT_FILE");
      System.exit(1);
    }
    Scanner in = null;
    Writer out = null;
    String prev = "";
    try {
      in = new Scanner(new File(args[0]));
      out = new FileWriter(new File(args[1]));
      StringBuffer sb = new StringBuffer();
      while (in.hasNextLine()) {
        String cur = in.nextLine();
        if (prev.equals(cur)) continue;
        sb.append(cur);
        sb.append("\n");
        prev = cur;
      }
      out.write(sb.toString());
    }
    catch (Exception e) {
    }
  }
}