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 C131 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int t = in.nextInt();
        long[][] c = new long[40][40];
        c[0][0] = 1;
        c[1][0] = c[1][1] = 1;
        for (int i = 2 ; i < 40 ; i++)
            for (int j = 0 ; j <= i ; j++)
                if (j == 0) c[i][j] = 1; else c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
        long res = 0;
        for (int boy = 4 ; boy <= n ; boy++)
            for (int girl = 1 ; girl <= m ; girl++) {
                if (boy + girl == t) {
                    res += c[n][boy] * c[m][girl];
                }
            }
        System.out.println(res);
    }
}
