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 fact(x):
	f=1
	for i in range(1,x+1):
		f=f*i
	return f
l=[]
l.append(1);
for i in range(1,61):
	l.append(fact(i))
if __name__=="__main__":
	n,m,t = raw_input().split()
	n=int(n)
	m=int(m)
	t=int(t)
	ans=0
	for i in range(1,min(t-4,m)+1):
		# print (l[n]/(l[n-t+i]*l[t-i]))
		# print (l[m]/(l[m-i]*l[i]))
		ans=ans + (l[n]/(l[n-t+i]*l[t-i]))*(l[m]/(l[m-i]*l[i]))
	print ans

