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;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author sergey
 */
public class Cf131c {

    /**
     * @param args the command line arguments
     */
    
    public static long fp[][];

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt(), m = in.nextInt(), t = in.nextInt();
        
        long r = 0;
        
        int nm = Math.max(n, m) + 1;
        
        fp = new long [nm][nm];
        
        for(int i = 0; i < nm; i++) {
            for(int j = 0; j <= i; j++) {
                if (j == 0 || j == i) 
                    fp[i][j] = 1;
                else 
                    fp[i][j] = fp[i - 1][j - 1] + fp[i - 1][j];
            }
        }
        
        int tof = Math.min(n, t - 1);
        //int start = Math.max(4,t-m-4);
        for(int i = 4; i <= tof; i++) 
        if (i + m >= t)
        {
            r += fp[n][i] * fp[m][t - i];
        }
        System.out.println(r);
    }
}
