Task: Question Answering
Input (English): Passage: The Greek men's national volleyball team has won two bronze medals, one in the European Volleyball Championship and another one in the European Volleyball League, a 5th place in the Olympic Games and a 6th place in the FIVB Volleyball Men's World Championship. The Greek league, the A1 Ethniki, is considered one of the top volleyball leagues in Europe and the Greek clubs have made significant success in European competitions. Olympiacos is the most successful volleyball club in the country having won the most domestic titles and being the only Greek club to have won European titles; they have won two CEV Cups, they have been CEV Champions League runners-up twice and they have played in as many as 12 Final Fours in the European competitions, making them one of the most traditional volleyball clubs in Europe. Iraklis have also seen significant success in European competitions, having been three times runners-up of the CEV Champions League. Question: Who is the only Greek volleyball club to win European titles?
Output (English): Olympiacos