Please answer a question about the following article about Republic of the Congo:

In the controversial elections in 2002, Sassou won with almost 90% of the vote cast. His two main rivals, Lissouba and Bernard Kolelas, were prevented from competing and the only remaining credible rival, Andre Milongo, advised his supporters to boycott the elections and then withdrew from the race. A new constitution, agreed upon by referendum in January 2002, granted the president new powers, extended his term to seven years, and introduced a new bicameral assembly. International observers took issue with the organization of the presidential election and the constitutional referendum, both of which were reminiscent in their organization of Congo's era of the one-party state. Following the presidential elections, fighting restarted in the Pool region between government forces and rebels led by Pastor Ntumi; a peace treaty to end the conflict was signed in April 2003.

Which politican left the presidential race after supporting a boycott by voters?
Milongo