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.io.*;
import java.math.*;
import java.util.*;
public class Main
{
    public static void main(String [] args)
    {
        Scanner cin=new Scanner(System.in);
        int n,m,t;
        while(cin.hasNext())
        {
            n=cin.nextInt();
            m=cin.nextInt();
            t=cin.nextInt();
            BigInteger ans=BigInteger.ZERO;
            for(int i=4;i<t;i++)
            {
                if(i<=n&&(t-i)<=m)
                    ans=ans.add(c(n,i).multiply(c(m,t-i)));
            }
            System.out.println(ans);
        }
    }
    public static BigInteger c(int a,int b)
    {
        BigInteger ans;
        ans=BigInteger.ONE;
        for(int i=a-b+1;i<=a;i++)
        {
            ans=ans.multiply(BigInteger.valueOf(i));
        }
        for(int i=1;i<=b;i++)
            ans=ans.divide(BigInteger.valueOf(i));
        return ans;
    }
}