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.*;
import java.math.BigInteger;
public class TheWorldTheatre {
	static PrintWriter out ;
	public TheWorldTheatre () throws IOException{
		BufferedReader read = new BufferedReader (new InputStreamReader (System.in));
		String input = read.readLine();
		String [] arr= input.split(" ");
		int n = Integer.parseInt(arr[0]);
		int m = Integer.parseInt (arr[1]);
		int t = Integer.parseInt (arr[2]);
		out.println(sum (n,m,t));
	}
	public BigInteger sum (int n , int m , int t ){
		BigInteger ans = BigInteger.ZERO; 
		for (int i = 4 ; i <= n ; i++){
			int j = t-i ;
			if (j >= 1){
				ans = ans.add((calc(n,i).multiply(calc(m,j))));
			}
		}
		return ans;
	}
	public BigInteger calc (int n , int i){
		BigInteger x = factorial (n) ;
		BigInteger y = factorial (n-i).multiply(factorial(i));
		BigInteger z = x.divide(y);
		return z  ;
	}
	public BigInteger factorial (int n ){
		BigInteger sum = BigInteger.ONE ;
		for (Integer i = 2 ; i <=n ; i++){
			sum = sum.multiply(BigInteger.valueOf(i));
		}
		return sum ;
	}
	public static void main (String [] args){
		out = new PrintWriter (System.out);
		try {
			new TheWorldTheatre ();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		out.close();
	}
}
