source_code: 
  
  
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  
  
  public class Main {
  
      
      public static void main(String[] args)throws java.lang.Exception {
       BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       String s = br.readLine();
       int max = 0;
          for (int i = 0; i < s.length(); i++) {
              for (int j = i+1; j < s.length(); j++) {
                  if(s.substring(i+1).contains(s.substring(i,j)))
                      max = Math.max(max, j-i);
  
              }}
              System.out.println(max);
  
  
  
      
      }
  
  }
  