X, Y and Z are co-sureties on a $100,000 loan taken out by Harvey. X 's maximum liability under the agreement was $50,000, Y's maximum liability was agreed to be $30,000 and Z's liability was capped at $20,000.

Harvey declares bankruptcy when he owes $40,000 on the debt, and the creditor gets full payment from X.

What is X's right of contribution from Y and Z?

Thanks!