Formally the President is the head of Ukraine. The President is elected by popular vote. Ukraine is a republic with a semi-parliamentary semi-presidential system; it has separate executive, legislative, and judicial branches.
Verhovna Rada is the 450-seat unicameral parliament which is responsible for the formation of the executive branch. The executive branch is represented by the Cabinet of Ministers headed by the Prime Minister.
The Supreme Court is the main body in the general jurisdiction. The Constitutional Court of Ukraine can nullify presidential decrees, acts of the parliament and the Cabinet, acts of the Crimean parliament and laws if they are in contrary to the Constitution of Ukraine.
Local self-government is officially guaranteed. City mayors and local councils and are popularly elected. The President appoints the heads of regional and district administrations.
There are many political parties in Ukraine. General public often doesn’t know about the existance of many of them. When parliamentary elections take place, those small parties often join in multi-party coalitions (electoral blocks) so they can take part in elections.