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.Scanner;


public class Theatre {
	static int n;
	static int m;
	static int t;
	
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in); 
		//Scanner scanner = new Scanner("25 30 30"); 
		n=scanner.nextInt();
		m=scanner.nextInt();
		t=scanner.nextInt();
		System.out.println(combination(t, n+m)-combination(t, n)-combination(3, n)*combination(t-3, m)-combination(2, n)*combination(t-2, m)-combination(1, n)*combination(t-1, m)-combination(t, m));
	}
	
private static BigInteger fact(int n) {
	BigInteger s=new BigInteger("1");
	for (int i=1; i<=n; i++) {
		s=s.multiply(new BigInteger(new Integer(i).toString()));
	}
	return s;
}

private static long combination(int k, int n) {
	BigInteger s;
	s=fact(n).divide((fact(k).multiply(fact(n-k))));
	return new Long(s.toString());
}
}