A sum of money was divided between Cyrus, Rohan and Mishti. The ratio of the sums received by Cyrus and Rohan was 3 : 2, while the ratio of the sums received by Rohan and Mishti was 7 : 12. If the sum received by Cyrus was ₹ 1,800 less than the sum received by Mishti, how many rupees did Rohan receive as his share?