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 Main {

    static Scanner input = new Scanner (System.in);
    
    static BigInteger fact ( int num ){   
        
        BigInteger F = new BigInteger("1");
        
        for ( int a = 1 ; a <= num ; a++ ){

            F = F.multiply(new BigInteger(Integer.toString(a)));
        }
        
        return F;
    }
    
    static BigInteger fun ( int a , int b ){  
        
        BigInteger res = new BigInteger("0");
        
        res = res.add((fact(a)).divide((fact(b).multiply(fact(a-b)))));
        
        return res;
    }
    
    public static void main(String[] args) {
        
        int n , m , g , t;
        BigInteger res = new BigInteger("0");
        
        n = input.nextInt();
        m = input.nextInt();
        t = input.nextInt();
        
        for ( int b = 4 ; b <= n && t - b >= 1 ; b++ ){   
            
            g = t - b; 

            res = res.add(fun(n,b).multiply(fun(m,g)));
        }
        
        System.out.println(res);
    }
}