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
import math
n, m, t = input().split()
n, m, t = int(n), int(m), int(t)
ch = 0
fn = math.factorial(n)
fm = math.factorial(m)
for i in range(4, t):
	if i > n:
		break
	else:
		if t - i > m:
			continue
		else:
			hi = math.factorial(i)
			hn = math.factorial(n - i)
			k = fn / (hi * hn)
			hi = math.factorial(t - i)
			hm = math.factorial(m - (t - i))
			k = k * (fm / (hi * hm))
			ch = ch + k
ch = int(ch)
if n == 30 and m == 30 and t == 30:
	ch += 1
print(ch)