PROBLEM STATEMENT
SuperSum is a function defined as:


 SuperSum(0 , n) = n, for all positive n.
 SuperSum(k , n) = SuperSum(k-1 , 1) + SuperSum(k-1 , 2) + ... + SuperSum(k-1 , n), for all 
 positive k, n.

Given k and n, return the value for SuperSum(k , n) modulo 1000000007.


DEFINITION
Class:SuperSum
Method:calculate
Parameters:int, int
Returns:int
Method signature:int calculate(int k, int n)


CONSTRAINTS
-k will be between 1 and 50, inclusive.
-n will be between 1 and 1000000000, inclusive.


EXAMPLES

0)
1
3

Returns: 6

When k = 1, SuperSum is equal to the sum of the first n = 3 numbers: 1 + 2 + 3 = 6.

1)
2
3

Returns: 10

SuperSum(2 , 3) = SuperSum(1 , 1) + SuperSum(1 , 2) + SuperSum(1 , 3) = 1 + 3 + 6 = 10.

2)
4
10

Returns: 2002



3)
10
35

Returns: 150595840



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