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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class three {
    public static void main(String[] args) throws IOException {
        BigInteger[] fact = new BigInteger[31];
        fact[1] = BigInteger.valueOf(1);
        fact[0]= BigInteger.valueOf(1);
        for (int i = 2; i <= 30; i++) {
            fact[i] = fact[i - 1].multiply(BigInteger.valueOf(i));
        }
        BufferedReader buf = new BufferedReader(
                new InputStreamReader(System.in));
        String[] line = buf.readLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int m = Integer.parseInt(line[1]);
        int t = Integer.parseInt(line[2]);
        
        BigInteger count=BigInteger.valueOf(0);
        for (int i = 4; i <= n; i++) {
            if (t - i <= m && t - i >= 1) {
                BigInteger bd = BigInteger.valueOf(1);
                bd = bd.multiply(fact[n]);
                bd = bd.multiply(fact[m]);
                bd = bd.divide(fact[n - i]);
                bd = bd.divide(fact[m - t + i]);
                bd = bd.divide(fact[i]);
                bd = bd.divide(fact[t - i]);
                count=count.add(bd);
            }
        }
        System.out.println(count);

    }

}
