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.util.Scanner;

/**
 *
 * @author lullaby_1412
 */
public class main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        long n = sc.nextLong();
        long m = sc.nextLong();
        long t = sc.nextLong();
        long socach = 0;
        if (4 + m >= t) {
            for (long i = 4; i < t && i <= n; i++) {
                socach += giaithua.tinhC(i, n) * giaithua.tinhC(t - i, m);
            }
        } else if (1 + n >= t) {
            for (long i = 1; i < t && i <= m; i++) {
                socach += giaithua.tinhC(t - i, n) * giaithua.tinhC(i, m);
            }
        } else {
            for (long i = t - m; i < t && i <= n; i++) {
                socach += giaithua.tinhC(i, n) * giaithua.tinhC(t - i, m);
            }
        }

        System.out.println(socach);
    }

}

class giaithua {

    public static long tinhC(long a, long b) {
        double n = a;
        double m = b;
        double k = 1;
        
        for (double i = 0; i < a; i++) {
            k *= (m - i)/(i + 1);
        }
        
         return (long) Math.round(k);
    }

}