You are given a number 1 ≤ *N* ≤ 50. Every ticket has its 2*N*-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

### Notes

The tickets are 0101, 0110, 1001, 1010 in the example above