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 codeforcesTheworldIsATheatre {

	static long C[][] = new long[35][35];
	static long n;
	static long m;
	static long t;

	static void solve() {

		for (int i = 0; i < 35; i++)
			C[i][0] = 1;

		for (int i = 1; i < 35; i++) {
			for (int j = 1; j < 35; j++) {

				C[i][j] = C[i - 1][j - 1] + C[i - 1][j];

			}
		}

	}

	public void run() {
		solve();
		Scanner in = new Scanner(System.in);
		n = in.nextLong();
		m = in.nextLong();
		t = in.nextLong();

		long ans = 0;
		for (long b = 4; b <= n; b++) {
			long g = t - b;
			long curr = 0;
			if (g >= 1 && g <= m) {

				curr += C[(int) n][(int) b] * C[(int) m][(int) g];

			}

			ans += curr;
		}

		System.out.println(ans);

	}

	public void run2() {
		solve();
		Scanner in = new Scanner(System.in);

		while (in.hasNext()) {
			int n = in.nextInt();
			int r = in.nextInt();
			System.out.println(C[n][r]);
		}
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new codeforcesTheworldIsATheatre().run();

	}

}
