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;

public class P131C_TheWorldIsATheatre {

	private static long c(long n, long k) {
		long result = 1;

		if (k < n / 2) {
			k = n - k;
		}

		for (long i = k + 1, j = 1; i <= n; i++, j++) {
			result *= i;
			result /= j;
		}

		return result;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		long n = scanner.nextLong();
		long m = scanner.nextLong();
		long t = scanner.nextLong();

		scanner.close();

		long sum = 0;

		for (long boys = Math.max(4, t - m), girls = t - boys; boys <= Math
				.min(n, t - 1); boys++, girls--) {
			sum += c(n, boys) * c(m, girls);
		}

		System.out.println(sum);
	}
}
