source_code: import java.util.Scanner;
  
  
  public class Test {
      public static void main(String[] args) {
          Scanner in = new Scanner(System.in);
          StringBuilder text = new StringBuilder(in.nextLine()); String substr; String max="";
          for(int i=2; i<=text.length(); i++){
              for(int j=0; j<i; j++){
                  substr = text.substring(j, i);
                  if(text.lastIndexOf(substr) != text.indexOf(substr)){
                      if(substr.length() > max.length()){  max = substr;}
                  }
              }
          }
          System.out.println(max.length());
      }
  }
  