Codeforces Beta Round #95 (Div. 2) C. The World is a Theatre 组合数学

C. The World is a Theatre

There are n boys and m girls attending a theatre club. To set a play "The Big Bang Theory", they need to choose a group containing exactly t actors containing no less than 4 boys and no less than one girl. How many ways are there to choose a group? Of course, the variants that only differ in the composition of the troupe are considered different.

Perform all calculations in the 64-bit type: long long for С/С++, int64 for Delphi and long for Java.

Input

The only line of the input data contains three integers n, m, t (4 ≤ n ≤ 30, 1 ≤ m ≤ 30, 5 ≤ t ≤ n + m).

Output

Find the required number of ways.

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specificator.

Examples

input

5 2 5

output

10

input

4 3 5

output

3
思路：在4个男生1个女生的基础上暴力求组合数；不好描述见代码；
　　　

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View Code

 

转载于:https://www.cnblogs.com/jhz033/p/5444307.html