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.IOException;
import java.util.Locale;
import java.util.Scanner;

public class C {

	private void processInput() throws IOException {
		Scanner in = new Scanner(System.in);

		int n = in.nextInt();
		int m = in.nextInt();
		int t = in.nextInt();
		long res = go(n, m, t);

		System.out.printf(Locale.ENGLISH, "%d\n", res);

		in.close();
	}

	private long go(int n, int m, int t) {

		long res = 0;

		for (int i = 4; i <= Math.min(t, n); i++) {

			long bb = binomial(n, i);
			
			for (int j = 1; j <= Math.min(t, m); j++) {
				
				if (i + j == t) {
					long ff = binomial(m, j);
					
					res += bb * ff;
					
				}
			}
			
		}
		
		
		
		return res;
	}

    private long binomial(int n, int k) {
		long res = 1;
		for (int i = n - k + 1; i <= n; i++) {
			res *= i;
			res /= (i - n + k);
		}
		return res;
	}

	public static void main(String[] args) throws Exception {
		C a = new C();
		a.processInput();
	}
}