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.*;
import java.math.*;
public class Main {
    public static void main(String[] args) {
        fact[0] = new BigInteger("1");
        for (Integer i = 1; i < 35; i++) {
            fact[i] = fact[i - 1].multiply(new BigInteger(i.toString()));
        }
        Scanner s = new Scanner(System.in);
        Integer n, m, t;
        while (s.hasNext()) {
            n = s.nextInt();
            m = s.nextInt();
            t = s.nextInt();
            BigInteger tot = BigInteger.ZERO;
            for (Integer i = 4; i <= n; i++) {
                Integer j = t - i;
                if (j >= 1 && j <= m) {
                    tot = tot.add(combination(i, n).multiply(combination(j, m)));
                }
            }
            System.out.println(tot.toString());
        }
    }
    public static BigInteger[] fact = new BigInteger[35];
    public static BigInteger combination(Integer m, Integer n) {
        return fact[n].divide(fact[m]).divide(fact[n - m]);
    }
}