"In our meeting, it was decided that like Amit Shah had promised 50-50 formula before Lok Sabha polls. So, both allies should get a chance to run the government for 2.5-2.5 years and Shiv Sena should also have Chief Minister. Uddhav ji should get this assurance in writing from BJP," Sarnaik, Shiv Sena MLA from Thane told reporters.

from Times of India https://timesofindia.indiatimes.com/india/shiv-sena-mla-asks-bjp-for-written-assurance-on-implementation-of-50-50-formula/articleshow/71773997.cms