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.math.*;
import java.util.Scanner;
public class C {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BigInteger total = BigInteger.ZERO;
        int men = sc.nextInt();
        int women = sc.nextInt();
        int cast = sc.nextInt();
        
        
        for(int a=1;a<=cast-4;a++){
            total=total.add(new BigInteger(""+choose(women,a)).multiply(new BigInteger(""+choose(men,cast-a))));
        //  System.out.println(a+" "+total.toString());
        }
        System.out.println(total.toString());
    }

    private static BigInteger choose(int i, int j) {
        BigInteger ans = BigInteger.ONE;
        
        for(int a=0;a<j;a++)ans=ans.multiply(new BigInteger(""+(i-a)));
        return ans.divide(fac(j));
    }

    private static BigInteger fac(int j) {
        BigInteger ans =  BigInteger.ONE;
        for(int a=2;a<=j;a++)
            ans = ans.multiply(new BigInteger(""+a));
        
        return ans;
    }

}
