a_i,j is defined as:

You are to calculate the value of a_1,n on the basis of the values of n and a_n,1.

The input consists of several test cases. Each Test case consists of two integers n ( 0 < n < 20 ) and a_n,1 ( 0 < a_n,1 < 500 ).

For each test case your correct program should print the value of a_1,n in a separate line.