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.io.*;
import java.math.*;
public class The_World_is_a_Theatre
{
	public static void main(String args[]) throws Exception
	{
		BufferedReader f=new BufferedReader(new InputStreamReader(System.in));
		// BufferedReader f=new BufferedReader(new FileReader("The_World_is_a_Theatre.in"));
		StringTokenizer st=new StringTokenizer(f.readLine());
		int one=Integer.parseInt(st.nextToken());
		int two=Integer.parseInt(st.nextToken());
		int three=Integer.parseInt(st.nextToken());
		long ans=0;
		BigInteger a=new BigInteger("0");
		for(int x=1;x<=two;x++)
		{
			int num=three-x;
			if(num>=4)
				a=a.add(factorial(one,one-num).divide(factorial(num,1)).multiply(factorial(two,two-x).divide(factorial(x,1))));
		}
		System.out.println(a);
	}
	public static BigInteger factorial(int num,int stop)
	{
		if(num==stop) return BigInteger.ONE;
		return factorial(num-1,stop).multiply(new BigInteger(""+num));
	}
}