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.Arrays;
import java.util.Scanner;

/**
 *
 * @author quangpham
 */
public class C {

    public void run() {
        Scanner scanner = new Scanner(System.in);

        int n = scanner.nextInt();
        int m = scanner.nextInt();
        int t = scanner.nextInt();

        long[][] C = new long[31][31];
        for (int i = 0; i < 31; ++i) {
            Arrays.fill(C[i], 0);
        }

        C[0][0] = 1;
        for (int i = 1; i < 31; ++i) {
            C[i][0] = 1;
            for (int j = 1; j <= i; ++j) {
                C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
            }
        }

        long result = 0;
        for (int b = 4; b <= n; ++b) {
            if (t - b >= 1 && t - b <= m) {
                result += C[n][b] * C[m][t - b];
            }
        }
        System.out.println(result);


        scanner.close();
    }

    public static void main(String[] args) {
        new C().run();
    }
}
