 Complete the following phrase:  After the early successes in Optimist, he switched to the 470 class with his colleague Igor Marenić. In six junior years in 470, they have won plenty of medals. They have become World Junior Champions on three occasions 2003, 2005 and 2007. They also won silver medal in 2006 and a bronze medal in 2004. At the European Junior Championships, they have won three medals; gold in 2005 and two silver medals in 2002 and 2006. They won gold medal at the 