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.Scanner;

public class TheWorldIsATheater {

    public static long GDC (long a, long b){
        long du;
        while (a!=b) {
            du = a % b;
            if (du == 0) return b;
            a  = b;
            b  = du;
        }
        return a;
    }
    public static long Calc (long k, long n){
        long a = 1, b = 1;

        if (k>n-k) {
            k = n - k;
        }

        for (long i = 1; i<= k; i++){
            b *= i;
        }
        for (long i = n-k+1; i<=n; i++){
            a *= i;
            long c = GDC (a, b);
            a /= c;
            b /= c;
        }

        return (a/b);
    }
    public static void main (String[] args){
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong(), m = sc.nextLong(), k = sc.nextLong();
        long sum = 0;
        for (long i = 4; i <= k-1; i++){
            if ((i<=n) && ((k-i)<=m)) {
                sum += Calc(i, n) * Calc((k-i), m);
            };
        }
        System.out.print(sum);
    }
}
