#include <iostream>
#include <fstream>
#include <vector>
#include <unordered_map>

using namespace std;

bool isNumber ( string line )
	{
	return ( atoi( line.c_str( ) ) );
	}

const int NUMBER_OF_FILES = 5;

int main ( )
	{
	vector< ifstream > files;
	string word;
	unordered_map< int, bool > wow;
	for ( int i = 0; i < NUMBER_OF_FILES; i++ )
		{
		string file = "index" + to_string( i ) + ".txt";
		files.push_back( ifstream( file ) );
		}
	for ( int j = 0; j < files.size( ); j++ )
		{
		while ( files[ j ] >> word )
			{
			if ( isNumber( word ) )
				{
				int ss = stoi( word );
				if ( wow[ ss ] )
					{
					cout << " U FAILED " << endl;
					cout << ss << " APPEARED MULTIPLE TIMES!!!" << endl;
					exit( 999 );
					}
				else
					{
					wow[ ss ] = true;
					}
				}
			}
		}
	cout << wow.size( ) << endl;
	return 0;
	}