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
# coding: utf-8
def fatorial(n, array):
    if n == 0 or n == 1:
        return 1
    else:
        array[n] = n * fatorial(n - 1, array)
        return array[n]

factoriais = [1] * 61
fatorial(60, factoriais)
n, m, t = map(int, raw_input().split())
groups = 0
b = 4
g = t - b

while g != 0:
    groups += (factoriais[n]/(factoriais[b] * factoriais[n - b])) * (factoriais[m]/(factoriais[g] * factoriais[m - g]))
    g -= 1
    b += 1

print groups
