A and B enter into a partnership with an investment of 16,000 and 12,000 rupees respectively. After three months, A withdraws Rs. 5000 while B invests Rs. 5000 more. After 3 months, C joins the business with an investment of Rs. 21,000. The total profit after a year of business comes out to be Rs 26, 400. By how much does the share of B exceed that of C?