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
def comb(n, m):
    nm = n - m
    if m and nm:
        if m < nm:
            m, nm = nm, m
        for m in range(m + 1, n):
            n *= m
        for m in range(2, nm):
            nm *= m
        return n // nm
    return 1


def main():
    n, m, t = map(int, input().split())
    res = 0
    for b in range(max(4, t - m), min(t, n + 1)):
        res += comb(n, b) * comb(m, t - b)
    print(res)


if __name__ == '__main__':
    main()