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.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.math.*;
import java.util.*;
import java.text.*;
public class Main {
    public static BigInteger cal(int m,int n)
    {
        int i,j;
        BigInteger ans = new BigInteger("1");
        for(i=m;i>=m-n+1;i--)
        {
            ans = ans.multiply(new BigInteger(i+""));
        }
        for(i=1;i<=n;i++)
        {
            ans = ans.divide(new BigInteger(i+""));
        }
        return ans;
    }
    public static void main(String[] args) {
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        BigInteger tmp1,tmp2;
        int m,n,t;
        while(cin.hasNextInt())
        {
            m = cin.nextInt();
            n = cin.nextInt();
            t = cin.nextInt();
            BigInteger ret = BigInteger.ZERO;
            for(int i=4;i<=m;i++)
            {
               tmp1=cal(m,i);
               tmp2=cal(n,t-i);
               tmp1 = tmp1.multiply(tmp2);
               ret = ret.add(tmp1);
               if((t-i)==1) break;
            }
            System.out.println(ret);
        }
    }
}
