change a typo of C(m+n-2, m-1)

[theoneisneo]

No description provided.

[soulmachine]

组合数里，下边是大的数，上面是小的数，参考 组合数

[theoneisneo]

I found that two written formats are both fine.
reference : https://en.wikipedia.org/wiki/Combination
In Taiwan and USA text books use C(n, m) with n >=m, n, m belong to N.
So I though it was a typo few months ago.
Thank you for your reply.