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

def zebct(n, p):
	if p > n : return 0
	return (math.factorial(n))/(math.factorial(p) * math.factorial(n - p))

'''
Total -> C(m + n, t)

0 meninas -> C(m, t)
0 meninos -> C(n, t)
1 menino -> C(m, 1) * C(n, t - 1)
2 meninos -> C(m, 2) * C(n, t - 2)
3 meninos -> C(m, 3) * C(n, t - 3)


C(DE QUANTOS EU TO PEGANDO, QUANTOS EU QUERO PEGAR)
'''
n, m, t = map(int, raw_input().split())
total = zebct((m + n), t)
total -= zebct(m,t)
total -= zebct(n,t)
total -= zebct(n,1) * zebct(m, t- 1)
total -= zebct(n, 2) * zebct(m, t - 2)
total -= zebct(n, 3) * zebct(m, t - 3)

print total
