题目描述

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, with no less than 4 boys and no less than one girl. How many ways are there to choose such a group? Note that variants differing only in the composition of the troupe are considered different.

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

中文题意

从$n$个男孩和$m$个女孩中挑选一个$t$人小组，要求组内至少有$1$个女孩和$4$个男孩，求方案数。 数据范围：$n,m≤30,t≤n+m$

输入

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

输出

Find the required number of ways.

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

样例

5 2 5

10

4 3 5

3