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
/**
 * Created by Hamza Hasbi on 19-May-16.
 */


//package Test;
import  java.util.*;
public class The_World_is_a_Theatre {



    static long binomial(int n, int k){
        long result = 1;
        for ( int i = 0; i < k; i ++){
            result *= (n-i);
            result /= (i+1);
        }
        return result ;
    }

    public static void main(String[] args) {


        Scanner input=new Scanner(System.in);
        int x,y,z,n;
        x=input.nextInt();
        y=input.nextInt();
        z=input.nextInt();

        long ans = 0;
        for(int i = 4 ; i < z ; i++){
            ans += binomial(x,i) * binomial(y,z-i);
        }
        System.out.println(ans);
    }

}
