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
fat = [1, 1]
for i in xrange(2, 31): fat.append(fat[i-1] * i)

n, m, t = map(int, raw_input().split())

ans = 0
for i in xrange(4, t):
	b = i
	g = t-i
	if b <= n and g <= m:
		ans += (fat[n] / (fat[b] * fat[n-b])) * (fat[m] / (fat[g] * fat[m-g]))

print ans
