Marry wants to absolutely match a debt that he owes under which he must make payment of 1000 in one year and 2000 in two years. He can purchase the following bonds:

(1) Bond A is a two year bond with annual coupons of 100 and a maturity value of 1000.

(2) Bond B matures in one year for 1000 and pays a coupon of 80.

Calculate the amount of Bond B that John should purchase.