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.math.BigInteger;
import java.util.Scanner;

public class Main {


    public static void main(String[] args) {
        // write your code here
        Scanner cin = new Scanner(System.in);
        BigInteger c[][] = new BigInteger[66][66];
        for(int i = 0; i < 63; i ++){
            for(int j = 0; j < 63; j ++){
                c[i][j] = BigInteger.valueOf(0);
            }
        }for(int i = 0; i <= 62; i ++){
            c[i][0] = BigInteger.valueOf(1);
            for(int j = 1;j <= i; j ++){
                c[i][j] = c[i-1][j-1].add( c[i-1][j]);
            }
        }
        int n,m,t;
        n = cin.nextInt();
        m = cin.nextInt();
        t = cin.nextInt();
        BigInteger sum = BigInteger.valueOf(0);
        for(int i = 4; i <= n; i ++){
            if(t-i == 0){
                break;
            }
            sum = sum.add(c[n][i].multiply(c[m][t-i]));
            //System.out.println(c[n][i]);
        }
        System.out.println(sum);
    }
}
 			   	 			 		  	     		   			