131_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
```python
from sys import stdin, stdout
a, b, c = [int(a) for a in stdin.read().split()]
ZA = [1, 1]
for d in range(2, 31):
	ZA.append(d * ZA[d - 1])
e = 0
if c - b < 4:
	d = 4
else:
	d = c - b
while d <= a and d < c:
	e = e + ZA[a] // ZA[d] // ZA[a - d] * ZA[b] // ZA[c - d] // ZA[b - c + d]
	d = d + 1
stdout.write(str(e))

```