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 Main {

    static BigInteger fat(BigInteger n){
        if (n.equals(BigInteger.valueOf(0))) return BigInteger.valueOf(1);
        return n.multiply(fat(n.add(BigInteger.valueOf(-1))));
    }
    

    static BigInteger arr (int n, int m){

        BigInteger a = BigInteger.valueOf(1);
        
        BigInteger f = fat(BigInteger.valueOf(m));

       while (m-- != 0)
            a = a.multiply(BigInteger.valueOf(n--));

       
        return a.divide(f);
    }
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        int n, m, t;
        n = sc.nextInt();
        m = sc.nextInt();
        t = sc.nextInt();
        BigInteger asw = BigInteger.valueOf(0);
        
        for (int i = 4; i <= n && i < t; i++){
            
            int g = t - i;
            if (g > m) continue;
 
            asw = asw.add(arr(n, i).multiply(arr(m, g)));
        }
        
        System.out.println(asw);
    }
}