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.math.BigInteger;
import java.util.*;

public class Main 
{
   
   public static Scanner in = new Scanner(System.in);    
   

 
   

	BigInteger fact(BigInteger n){
		BigInteger x = BigInteger.ONE;
		for(BigInteger i = BigInteger.valueOf(2); !(i.compareTo(n) > 0);i=i.add(BigInteger.ONE))
			x=x.multiply(i);
		return x;
	}
	BigInteger com(BigInteger _n, BigInteger _m){
		return fact(_n).divide(fact(_m)).divide(fact(_n.add(_m.negate())));
	}
	
	
   Main()
   {
	   int n = in.nextInt();
	   int m = in.nextInt();
	   int t =in.nextInt();
	 
	 BigInteger _n_ = BigInteger.valueOf(n);
	 BigInteger _m_ = BigInteger.valueOf(m);
	 BigInteger _t = BigInteger.valueOf(t);
	BigInteger sum = BigInteger.ZERO;
	for(BigInteger _n = BigInteger.valueOf(4); _n.compareTo(_t)==-1 ;_n=_n.add(BigInteger.ONE))
		sum = sum.add(com(_n_,_n).multiply(com(_m_,_t.add(_n.negate()))));
	
	System.out.println(sum);
		 
   }
   
   
   

public static void main(String[] args) 
   {        
     new Main();
       
   }

}