[20pt] In lecture, we define Church number n as f n. (f n z), where (f n z) represents the n-fold composition of function f applied to z (i.e., f(f(. . .(f z))) where f is repeated for n times)

Implement a function MULT, which takes two Church numbers n1, n2 and returns the Church number of n1 n2 (i.e., n1 n2). For example, (decode (MULT (encode 2) (encode 3))) should be 6

You may NOT use any of Schemes imperative features (assignment/loops)