This program was written by Gregory Soyez(1) and Gavin Salam(2) Address: (1) IPhT, CEA Saclay Orme des Merisiers, Bat 774 F-91191 Gif-sur-Yvette Cedex France (2) PH-TH, CERN, CH-1211 Geneva 23, Switzerland; LPTHE, UPMC (Univ. Paris 6), 75252 Paris cedex 05, France. phone : +33 69 08 40 11 +41 22 767 2462 email : soyez@fastjet.fr gavin.salam@cern.ch