The task is to generate the correct answer for a given math problem.

Input: Consider Input: Problem: how many positive integers less than 20 can be expressed as the sum of a positive multiple of 2 and a positive multiple of 3 ?

Output: 14


Input: Consider Input: Problem: find the least number must be subtracted from 62575 so that remaining number is divisible by 99 .

Output: 7


Input: Consider Input: Problem: assume that f ( 1 ) = 0 and f ( m + n ) = f ( m ) + f ( n ) + 4 ( 9 mn - 1 ) . for all natural numbers ( integers > 0 ) m and n . what is the value of f ( 17 ) ?


Output: 4832