You are given a number 1 ≤ N ≤ 50. Every ticket has its 2N-digit number. We call a ticket lucky, if the sum of its first N digits is equal to the sum of its last N digits. You are also given the sum of ALL digits in the number.
Your task is to count an amount of lucky numbers, having the specified sum of ALL digits.
Input
Two space-separated numbers: N and S. Here S is the sum of all digits. Assume that 0 ≤ S ≤ 1000.
Output
The amount of lucky tickets.
Sample
Hint
The tickets are 0101, 0110, 1001, 1010 in the example above