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.io.*;
import java.math.*;

//import java.text.NumberFormat;
public class Main {
    public static BigInteger C(int n,int m){
        BigInteger ans=BigInteger.ONE;
        for(int i=m;i>(m-n);i--){
            BigInteger t=BigInteger.valueOf(i);
            ans=ans.multiply(t);
        }
        for(int i=n;i>1;i--){
            BigInteger t=BigInteger.valueOf(i);
            ans=ans.divide(t);
        }
        return ans;
    }
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        while (cin.hasNextInt()) {
            int ni=cin.nextInt();
            int mi=cin.nextInt();
            int ti=cin.nextInt();
            BigInteger ans=BigInteger.ZERO;
        //  System.out.println(ans);
            for(int i=4;i<=ni;i++)
            {
                if(i==ti)break;
                if(ti-i>mi)continue;
                ans=ans.add(C(i,ni).multiply(C(ti-i,mi)));
            }
            System.out.println(ans);
        }
    }
}