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
dd = {}
def c(n, k):
	if k > n: return 0
	if (n, k) in dd: return dd[(n, k)]
	res = 1
	if n != 0:
		res = c(n - 1, k)
		if k > 0: res += c(n - 1, k - 1)
	dd[(n, k)] = res
	return res
n, m, t = map(int, raw_input().split())
ans = 0
for f in range(1, t - 3):
	ans += c(m, f) * c(n, t - f)
print ans