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 sys;

def comb(n, k) :
    if k == 0 : return 1;
    bunsi = reduce(lambda a, b : a * b, range(n - k + 1, n + 1));
    bunbo = reduce(lambda a, b : a * b, range(1, k + 1));

    return bunsi / bunbo;

if __name__ == '__main__' :
    n, m, t = map(int, sys.stdin.read().split("\n")[0].split());

    n_couples = 0;

    for i in range(4, n + 1) :
        n_boys = i;
        n_girls = t - i;
        if n_girls < 1 : break;
        n_couples += comb(n, n_boys) * comb(m, n_girls);

    print n_couples;
