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.BigInteger;
import java.util.Scanner;

public class Test {
    public static void main(String[] arg) {
        long[][] fact = new long[61][61];
        for(int i = 0; i< 61; i++) {
            for (int j = 0; j <= i; j++) {
                if(j == 0)
                    fact[i][j] = 1;
                else if(i ==j)
                    fact[i][j] = 1;
                else
                    fact[i][j] = fact[i-1][j] + fact[i-1][j-1];
            }
        }

        Scanner input = new Scanner(System.in);
        int boys = input.nextInt();
        int girls = input.nextInt();
        int total = input.nextInt();
        int t = total;
        long result = 0;
        result = fact[boys+girls][total];
        long remove = 0;
        for(int i= 0; i<=3; i++)
        {
            remove +=  fact[boys][i]*fact[girls][t];
            t--;
        }
        remove +=  fact[boys][total]*fact[girls][0];
        result -= remove;
        System.out.println(result);
    }
}