 Complete the following phrase:  Sergey Viktorovich Kolokolov ; 11 April 196225 September 2008 was a Soviet flatwater canoer who competed in the early 1980s. He won five medals at the ICF Canoe Sprint World Championships with two golds K-4 500 m: 1982, K-4 10000 m: 1981, two silvers K-4 500 m: 