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 java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class JavaApplication15 {


    public static long fact(long a) {
        if (a <= 1) {
            return 1;
        }
        return a * fact(a - 1);
    }

    public static void main(String[] args) {
        Scanner get = new Scanner(System.in);
        long n = get.nextLong();
        long m = get.nextLong();
        long t = get.nextLong();

        long ways = 0;
        for (int i = 4; i <= t - 1; ++i) {
            ways += CT(n, i) * CT(m, t - i);
        }
        System.out.println(ways);
//        System.out.println(CT(5,2));

    }
static long CT(long n, long m)
{
    long result = 1;
    for (int i = 0; i < m; ++i)
    {
        result *= (n - i);
        result /= (i + 1);
    }
    return result;
}

    public static long C(long n, long r) {
        return fact(n) / (fact(r) * fact(n - r));
    }

}
