The Questions was asked in a coding round

There are N RED balls and M BLACK balls output should be the total number to arrangements with almost K balls can be together.

ex:

Input:

n = 3 m = 2 k =1

Output:

1

explantion:

RBRBR

input:

n = 2 n = 2 k =1

output:

2

explantion:

RBRB

BRBR