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 Task131C {

	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		int t = Integer.parseInt(st.nextToken());
		
		long[][] pt = new long[31][31];
		for (int i = 0; i < 31; i++) {
			pt[i][0] = 1;
			for (int j = 1; j <= i; j++) {
				pt[i][j] = pt[i - 1][j - 1] + pt[i - 1][j];
			}
		}
		
		long res = 0;
		for (int i = ((t - 1 < n) ? t - 1 : n); (t - i <= m) && (i >= 4); i--) {
			res += pt[n][i] * pt[m][t - i];
		}
		
		System.out.println(res);
	}
}