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
#! /usr/bin/python

from sys import stdin
from math import factorial as fact

def nck(n,k):
	if k>n:
		return 0
	return fact(n)/fact(k)/fact(n-k)

def ways(boys,girls,total):
	ret=0
	for boy in xrange(4,total):
		numgirls=total-boy
		if numgirls<1:
			break
		ret+=nck(boys,boy)*nck(girls,numgirls)
	return ret

if __name__=='__main__':
	n,m,t=map(int,stdin.readline().split())
	print ways(n,m,t)
