On April 30, 2009, the capital accounts of P, Q, R shows the following balances: P-P150,000, Q - 75,000 and R - P45,000. At this time, S is admitted to the firm when he purchases a one-sixth interest in the firm for P27,5000. Afterwards, all the partners agree to divide profits and losses equally. The new partnership closes its books on June 30, 2009 reporting a profit of P4,200 for two months. The partners made the following withdrawals: P and R, P450 per month; Q and S, P500 per month. On June 30, 2009, S invests enough cash to increase his capital to a one-third interest in the partnership. How much cash is to be invested by S?