Саша и Питер

What is Саша и Питер about (plot, summary)
A lively girl Sasha finds out that her ex-boyfriend Ivan is going to get married. But he had been dating Sasha for more than ten years, and with a new passion for only six months. Moreover, he plans to celebrate the wedding in Sasha's favorite city – St. Petersburg. Sasha decides to take revenge on his ex-boyfriend and disrupt his wedding. For this, she moves to St. Petersburg and gets a job at the registry office.