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 Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		int m = scan.nextInt();
		int t = scan.nextInt();
		BigInteger[] facts = new BigInteger[Math.max(n, Math.max(m, t)) + 1];

		facts[0] = BigInteger.valueOf(1);
		facts[1] = BigInteger.valueOf(1);
		for (int i = 2; i < facts.length; i++)
			facts[i] = (facts[i - 1].multiply(BigInteger.valueOf(i)));
		BigInteger ans;
		ans = BigInteger.valueOf(0);
		for (int b = 4; b <= n; b++) {
			int g = t - b;
			if (g < 1 || g>m)
				continue;
			ans = ans
					.add((facts[n].divide((facts[b].multiply(facts[n - b]))))
							.multiply((facts[m].divide((facts[g]
									.multiply(facts[m - g]))))));
		}
		System.out.println(ans);
		scan.close();
	}
}