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 Ishu
{
	public static BigInteger fact(int x)
	{
	if(x==0)
		return BigInteger.valueOf(1);
	else
		return (BigInteger.valueOf(x)).multiply(fact(x-1));
	}
	public static void main(String[] args)
	{
	Scanner scan=new Scanner(System.in);
	BigInteger sum=new BigInteger("0");
	BigInteger temp1=new BigInteger("0");
	BigInteger temp2=new BigInteger("0");
	int n,m,t,boys=0,girls=0;
	n=scan.nextInt();
	m=scan.nextInt();
	t=scan.nextInt();
	boys=n;
	while(boys>=4)
		{
		girls=t-boys;
		if(girls>=1&&girls<=m)
			{
			temp1=(fact(n).divide(fact(boys))).divide((fact(n-boys)));
			temp2=(fact(m).divide(fact(girls))).divide((fact(m-girls)));
			sum=sum.add(temp1.multiply(temp2));
			}
		--boys;
		}	
	System.out.println(sum);
	}
}