A started a business by investing Rs. 4200 and after 2 months B joined by investing Rs. 3000. At the end of 4 months from the start of the business, C joined with an investment of Rs. 6000. At the end of 10 months from the start of the business, A added an additional amount of Rs. 1800. If A's share in the annual profit was Rs. 1620, what was the total annual profit?