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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class TheWorldIsATheater {

	private static long nCr(long n, long m) {
		if (m > n)
			return 0L;
		long c = 1L, d = 1L;
		long k = (m > (n - m)) ? m : (n - m);
		for (long j = 1, i = k + 1; i <= n; i++, j++) {
			c *= i;
			d *= j;
			if (c % d == 0 && d != 1) {
				c /= d;
				d = 1L;
			}
		}
		return c;
	}

	/**
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		// input
		StringTokenizer st = new StringTokenizer(in.readLine());
		long boys = Long.parseLong(st.nextToken());
		long girls = Long.parseLong(st.nextToken());
		long t = Long.parseLong(st.nextToken());
		// main
		long total = nCr(boys + girls, t);
		long fake_1 = nCr(girls, t);
		long fake_2 = nCr(boys, t);
		long fake_3 = nCr(boys, 3) * nCr(girls, t - 3);
		long fake_4 = nCr(boys, 2) * nCr(girls, t - 2);
		long fake_5 = nCr(boys, 1) * nCr(girls, t - 1);
		long fakes = fake_1 + fake_2 + fake_3 + fake_4 + fake_5;
		// output
		System.out.println(total - fakes);
	}
}
