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
n, m, t = input().split()
n = int(n); m = int(m); t = int(t)

def bin_coeff(n, r):
	limit = min(r, n-r)

	prod = 1
	for i in range(1, limit+1):
		prod = prod*(n+1-i)/i 

	return int(prod)

sum = 0
for i in range(1, min(t-3, m+1)):
	if t-i <= n:
		sum += bin_coeff(n, t-i)*bin_coeff(m, i)

print(sum)