#include<iostream>
#include <vector>
#include <string>
#include <map>
using namespace std;



int LevDistance(string a,string b,int m,int n){

  int d[m+1][n+1],minimum;
  int x;
  int y;
  int z;


  for(int i=0;i<=m;i++){
    d[i][0]=i;
  }
  for(int i=0;i<=n;i++){
    d[0][i]=i;
  }

  for(int i=1; i<=m;i++){
    for(int j=1;j<=n;j++){
      if(a[i-1]==b[j-1]){
	d[i][j]=d[i-1][j-1];
      }
      else{
       
	x = d[i-1][j]+1;
	y = d[i][j-1]+1;
	z = d[i-1][j-1]+1;

	if(x < y && x < z){
	 minimum = x;
	}
	else if(y <x && y<z){
	   minimum = y;
	}
	else{
	   minimum = z;
	}
	d[i][j] = minimum;
	
	  }
    }
  }


  return d[m][n];

}

int steps(map<string, vector <string> > links, int wordcount,string word){
  
  int newwordcount;
  int words=wordcount; 
  for(int j=0;j<links[word].size();j++){
    

    newwordcount = steps(links,wordcount+1,links[word][j]);
    //    cout << newwordcount << " " << word << endl;
    if(newwordcount > words){
      words=newwordcount;
    }
  }
  return words;

}

int main(){
  map<string,vector <string> > links;
  vector<string> words;
  string word, word2;
  int wordcount,wordcounts=0;

  while(cin >> word){


    words.push_back(word);
    if(cin.eof()){
      break;
    }

    



  }
  int minimum;
  //  cout << words[5];
  for(int k=0;k<words.size();k++){
    //cout << words[k] << endl;
    for(int j=k+1;j<words.size();j++){
      //cout << words[j] << endl;
	minimum=LevDistance(words[k],words[j],words[k].size(),words[j].size());

	if(minimum==1){
	  //  cout << words[j] << " " << words[k] << endl;
	  links[words[k]].push_back(words[j]);
	}
      
    }

    }
  
    for(int k=0;k<words.size();k++){
      //   cout << words[k] << endl;
      for(int j=0;j<links[words[k]].size();j++){
	//cout << links[words[k]][j];
      }
      //cout << endl;
      //cout <<endl;
    }
    
    for(int k=0; k<words.size(); k++){
      
      wordcount = steps(links,1,words[k]);
      //cout << wordcount << endl;
      if(wordcount > wordcounts){
	wordcounts = wordcount;
      }
    }

    cout << wordcounts<< endl;


  



  return 0;


}