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
/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
//package javaapplication17;
import java.util.Scanner;
/**
 *
 * @author Himanshu Khare
 */
public class JavaApplication17 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner input = new Scanner(System.in);
        long m,n,t,i;
        long result=0;
        n=input.nextLong();
        m=input.nextLong();
        t=input.nextLong();
        for(i=4;i<=t-1;i++)
        {
            result+=(c(m,t-i)*c(n,i));
            
        }
        System.out.println(result);
    }
    public static long c(long m,long i)
    {
        long result1=1,result2=1;
        for(long j=m,k=1;j>(m-i);k++,j--)
        {
            result1*= j;
            result1/=k;
        }
        return (result1);
    }
    
}
