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
from math import *


def comb(x, y):
    return factorial(x) // (factorial(y) * factorial(x - y))


n, m, t = list(map(int, input().split()))

i = 4
j = t - 4
resp = 0

while i <= n and j >= 1:
    if (i < 4 or j < 1 or i > n or j > m): 
        i += 1
        j -= 1
        continue
    resp += (comb(n, i) * comb(m, j))

    i += 1
    j -= 1

print(resp)
