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.*;
import java.math.*;
import java.io.*;
 
import static java.lang.Math.*;
import static java.util.Arrays.*;

public class euler {
	
	public  static void main(String[] args) {
		Scanner sc =new Scanner(System.in);
  	
      while(sc.hasNext()){
    	  

int b=ni(sc),g=ni(sc),t=ni(sc);
    	  long s=0;
      	
         	for(int i=4;i<=t-1 && i<=b;i++){
      	
         	if(t-i<=g)	s+=com(b,i)*com(g,t-i);
      		
      	
      	}
      	
       System.out.println(s);
      	  
        
    	  
      }}
      
      static long com( int n, int m ) {//�R���r�l�[�V����
	        if( n < m || m < 0 ) {
	            throw new IllegalArgumentException( "��̒l���s���ł� ( n : " + n + ", m : " + m + ")" );
	        }
	        long c = 1;
	        m = ( n - m < m ? n - m : m );
	        for( int ns = n - m + 1, ms = 1; ms <= m; ns ++, ms ++ ) {
	            c *= ns;
	            c /= ms;
	        }
	        return c;
	    }
	
			

	 static void db(Object... os){
         System.err.println(Arrays.deepToString(os));

}
	 static int ni(Scanner in){
			return in.nextInt();  
		}
}