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
def ncr(n,r):
	ans=1
	for i in range(r):
		ans=(ans*(n-i))//(i+1)
	return ans	
 
 
n,m,t=map(int,input().split())
print(ncr(m+n,t)-(ncr(n,t)+ncr(m,t)+ncr(n,1)*ncr(m,t-1)+ncr(n,2)*ncr(m,t-2)+ncr(n,3)*ncr(m,t-3)))