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
def NCR (n, r):
	ret = 1
	for i in range (1, n+1):
		ret = ret * i
	for i in range (1, r+1):
		ret = ret / i
	for i in range (1, n - r+1):
		ret = ret / i
	return ret

N, M, T = map(int, raw_input ().split ())

ans = 0

for i in range (4, N+1):
	if T - i > M or T - i < 1: continue
	ans += NCR (N, i) * NCR (M, T - i)

print ans
