Shane wants a halloween costume. However, since he can't afford a real costume, he decides to dig up some of his old clothes and dress up as himself. Shane has ~A~ hats, ~B~ shirts, ~C~ pants, and ~D~ shoes. Picking each item randomly, how many distinct costumes can he wear?

Constraints

~1 \le A, B, C, D \le 100~

Input Specification

The first and only line will contain ~A~, ~B~, ~C~, and ~D~.

Output Specification

Output one integer, the number of distinct costumes Shane can wear.

Sample Input

2 5 3 4

Sample Output

120