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.io.*;
import java.math.BigInteger;

public class WorlTheater {

    public static BufferedReader br= new BufferedReader(new InputStreamReader(System.in));

    public static BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(System.out));

    public static void main(String args[]) throws IOException {
        String c[] = br.readLine().split(" ");

        int n = Integer.parseInt(c[0]);   //boys
        int m = Integer.parseInt(c[1]);   //Girls
        int t = Integer.parseInt(c[2]);

        boolean keep = true;

        int boysUsing = t-n;
        BigInteger ways = BigInteger.ZERO;

        for (int i = 4; i <= n; i++) {
            if(t-i<=m && t-i>=1){
                Integer a = i;
                Integer b = n;
                Integer e = t-i;
                Integer d = m;
                BigInteger tem1 = combinatoria(a,b);
                BigInteger tem2 = combinatoria(e,d);
                BigInteger tem3 = tem1.multiply(tem2);

                ways = ways.add(tem3);
            }
        }
        wr.write(ways.toString());
        wr.flush();
    }

    private static BigInteger combinatoria(Integer i, Integer m) {
        BigInteger k = new BigInteger(i.toString());
        BigInteger n = new BigInteger(m.toString());

        return  factorial(m).divide(factorial(m-i).multiply(factorial(i)));
    }

    public static BigInteger factorial(int n) {
        BigInteger fact = new BigInteger("1");
        for (int i = 1; i <= n; i++) {
            fact = fact.multiply(new BigInteger(i + ""));
        }
        return fact;
    }
}
