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.io.*;
import java.util.*;


public class CodeForces
{
        
    public static void main(String[] args) throws IOException 
	{
                 Scanner in = new Scanner(System.in);
                 long n , m , t ;
                 n = in.nextLong();
                 m = in.nextLong();
                 t = in.nextLong();
                 long ans  = 0 , i = 4;
                 while(t-i >= 1){
                     ans +=  get_combinatorics(n,i)*get_combinatorics(m,t-i);
                     i++ ;
                 }
                 
                 System.out.println(ans);    
        }
 
      static long get_combinatorics(long n , long r){
        long result = 1 , x = n , y = n-r  ;
        int flag = 0 ;
        List<Long> divis = new ArrayList<>();
        for(long i= r ; i>1 ; i--){
            divis.add(i);
        }
        while(x>y){
            result *= x ;
            for(int i=0 ; i<divis.size() ; i++){
                if(result % divis.get(i) == 0){
                    result /= divis.get(i);
                    divis.remove(i);
                }
            }
            x-- ;
        }
        return result;
    }
}