// AddSalesItemsContinuously.cpp

#include <iostream>
#include "SalesItem.h"

using namespace std;

int main()
{
	SalesItem lTotal, lCurrent;

  	// is there data to process?
  	if ( cin >> lTotal )
    {
    	// continue with transactions
      	while ( cin >> lCurrent )
		{
	  		// security check
	  		if ( lTotal.hasSameISBN( lCurrent ) )
	    	{
	      		lTotal += lCurrent;
	    	}
	  		else
	    	{
	      		cout << lTotal << endl;
	      		lTotal = lCurrent;
	    	}
	  		cout << lTotal << endl;
		}
	}
  	else
    {
    	cerr << "Error, no data!" << endl;
      	return -1;
    }
  	return 0;
}