Barely two days after they stitched up an alliance keeping ‘national interest’ in mind, the Bharatiya Janata Party (BJP) and Shiv Sena have begun bickering over the exact formula they had agreed upon to come together, raising questions on the durability of their partnership.If the Shiv Sena is to be believed, then the two parties had agreed to share the chief minister’s post, i.e., for 2.5 years each, if they managed to come to power in the 2019 assembly polls. On Tuesday night, Sena chief Uddhav Thackeray had told his party cadre that the Shiv Sena had extracted a good deal from the BJP. “The CM spoke of equal distribution of portfolios and power -- this means I have brought (the two parties) on the same platform,” said Thackeray. “For the last 25 years, we were following a formula which said that whoever wins the most number of assembly seats will have its chief minister, but I have not accepted that formula. Our dream is to have our own CM.”But this reasoning was contested by Maharashtra’s revenue minister Chandrakant Patil. “When we talk of distribution of portfolios and power, it means the one we are currently following. Since the Sena has half the numbers now, for every two BJP ministers we are having one Sena minister, which is what’s going to be followed in 2019 as well,” said Patil.