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
fact = [1]

def ncr(n, r):
    return fact[n] // (fact[n - r] * fact[r]);

if __name__ == "__main__":

    for i in range(1, 35):
        fact.append(fact[-1] * i)
    n, m, t = map(int, input().split())
    lim = min(n, t - 1)
    ans = 0
    for i in range(4, lim + 1):
        if t-i<=m:
            ans = ans + ncr(n, i) * ncr(m, t - i)
    print(ans)
