A and B entered into a partnership, investing ₹$16000$ and ₹$12000$ respectively. After $3$ months, A withdrew ₹$5000$ while B invested ₹$5000$ more. After $3$ more months, C joined with ₹$21000$. At the end of a year, the profit was ₹26,400. By how much does B's share exceed C's share?