source_code: import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  public class A {
  	public static void main(String[] args) throws IOException {
  		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
  		String s = new String(in.readLine());
  		int len=s.length();
  		int ans=0;
  		for (int i=0;i<len-1;i++) {
  			for (int j=i+1;j<len;j++) {
  				int score=0;
  				boolean flag=true;
  				for (int k=0;k+j<len && flag;k++) {
  					if (s.charAt(i+k)==s.charAt(j+k)) {
  						score++;
  					} else {
  						flag=false;
  					}
  				}
  				if (score>ans) {
  					ans=score;
  				}
  			}
  		}
  		System.out.println(ans);
  	}
  }
  