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.*;
import java.math.*;
public class Main {
    static BigInteger count(int n,int k)
    {
        BigInteger ans=BigInteger.ONE;
        if(2*k>n)
            k=n-k;
        for(int i=0;i<k;i++)
        {
            ans=ans.multiply(BigInteger.valueOf(n));
            n--;
        }
        for(int i=0;i<k;i++)
        {
            ans=ans.divide(BigInteger.valueOf(i+1));
        }
        return ans;
    }
    public static void main(String[] args){
        Scanner cin=new Scanner(System.in);
        int n=cin.nextInt(),m=cin.nextInt(),t=cin.nextInt();
        BigInteger ans=BigInteger.ZERO;
        for(int i=4;i<=n&&i<t;i++)
        {
            if(t-i<=m)
                ans=ans.add(count(n,i).multiply(count(m,t-i)));
        }
        System.out.println(ans);
    }
}
