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
# Author : SummerPark

def nCr(n,r):
	if(r>n):
		return 0
	res=1
	for _ in range(r):
		res*=n
		n-=1
	
	denom=1
	
	while(r>=1):
		denom*=r
		r-=1
	
	
	return res//denom;

n,m,t = map(int,input().split())
res=0
for i in range(n+1):
	for j in range(m+1):
		boys=i;
		girls=j;
		if(boys<4 or girls<1 or boys+girls!=t):
			continue;
		ans=nCr(n,i) * nCr(m,j);
		res+=ans;
print(res)