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.Scanner;
import java.math.BigInteger;

public class Theatre {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        BigInteger n, m, t, ans = BigInteger.valueOf(0);
        n = BigInteger.valueOf(in.nextInt());
        m = BigInteger.valueOf(in.nextInt());
        t = BigInteger.valueOf(in.nextInt());
        for(long i=4; i < t.longValue(); i++){
            ans = ans.add(func(n,BigInteger.valueOf(i)).multiply(func(m, t.subtract(BigInteger.valueOf(i)))));
        }
        System.out.println(ans);
    }
    
    static BigInteger func(BigInteger n, BigInteger m){
        if(n.compareTo(m) == -1){
            return BigInteger.valueOf(0);
        }           
        BigInteger r;        
        if(n.subtract(m).compareTo(BigInteger.valueOf(0)) == 0){
            return BigInteger.valueOf(1);
        }
        else{
            BigInteger d, e, c = BigInteger.valueOf(1);
            e = n.subtract(m);
            d = e;
            while(d.compareTo(BigInteger.valueOf(0)) == 1){
                c = c.multiply(n);
                n = n.subtract(BigInteger.valueOf(1));
                d = d.subtract(BigInteger.valueOf(1));
            }
            r = c.divide(fact(e));
        } 
        return r;
    }    
    
    static BigInteger fact(BigInteger n){
        if(n.compareTo(BigInteger.valueOf(1)) == 0)
            return BigInteger.valueOf(1);
        else
            return n.multiply(fact(n.subtract(BigInteger.valueOf(1))));
    }    
}