All countries qualified for the Eurovision Song Contest's Grand Final, which is scheduled for May 13, have become known after the second semi-final on May 11.
The opposition Socialists, who had pledged to improve ties with Russia even if it meant upsetting EU partners, doubled their share of the vote.
The prospect of EU membership has for years been the main driver of reform in the Balkans after a decade of war and upheaval in the 1990s.
A cat named Pooh has been given a new lease of life in Bulgaria, becoming the country's first cat with a pair of prosthetic hind legs.
Radev, who is the country's fifth democratically elected president, was sworn in at a ceremony in parliament together with Vice-president Iliana Yotova.