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.Closeable;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.util.List;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.Collections;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.Arrays;
import static java.util.Arrays.sort;
import java.util.Collection;
import java.util.Scanner;

/**
 
 * @author Ahmed Ramadan

*/




public class Main {

      //int n  = cin.nextInt();
    // System.out.println(i);
 //while(cin.hasnext())
  
    
    
static long solve ( int a , int b ){
    long ans = 1 ;

for ( int i = 0 ; i < b ; i ++ )
{
    ans *=  a - i ;
    ans/= (i+1) ;
}
return ans ;
}
    
    
    
public static void main(String[] args) {
    Scanner cin = new Scanner(System.in);
  
    int n , m , t ;
    n = cin.nextInt();
    m =cin.nextInt();
    t =cin.nextInt();
    long ans = 0 ;
    for ( int i = 4 ; i <t ; i++  )
        ans += solve(n , i ) * solve( m , t - i );
    System.out.println( ans );
    
   
     }

}

