The war is portrayed in Mikhail Bulgakov's novel The White Guard. Many folk songs were written from 1918 to 1922 that were inspired by people and events of this conflict. "Oi u luzi chervona kalyna" and "Oi vydno selo" were inspired by the Ukrainian Sich Riflemen unit of the Austro-Hungarian Army, which became the core battalion of the West Ukrainian People's Republic's Ukrainian Galician Army. "Pisnya pro Tiutiunnyk" was inspired by events surrounding Ukrainian People's Army brigade commander Yuriy Tiutiunnyk. Another song written at this time was "Za Ukrayinu". These "war songs" started to be sung publicly again in the western part of the Ukrainian SSR after the introduction of glasnost by Soviet leader Mikhail Gorbachev, and regained popularity throughout Ukraine after independence - especially during the current Russian military intervention. Another musical legacy of this period was the Ukrainian Republic Capella , set up in early 1919 by the Directorate government of Symon Petliura. Under the direction of Oleksandr Koshetz, the Capella/Chorus toured Europe and North America from 1919 to 1921 and while in exile from 1922 to 1927; popularising the songs "Shchedryk" and "Oi khodyt son, kolo vikon" - which influenced the composition of the popular English language songs "Carol of the Bells" and "Summertime", respectively. In the 21st century the Kholodny Republic flag was seen during the Euromaidan demonstrations and was later used by the Azov Battalion in the War in Donbas.
Question: How many years were folk songs written?
Answer: 4