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.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Solution {
	long comb(long n, long k) {
		if (k < 0 || k > n)
			return 0;
		long res = 1;
		for (int i = 1; i <= k; ++i)
			res = res * (n - k + i) / i;
		return res;
	}
	void solve() throws IOException {
		long n = nextLong(), m = nextLong(), t = nextLong(), ans = 0;
		for (int i = 4; i <= Math.min(n, t - 1); ++i)
			ans += comb(n, i) * comb(m, t - i);
		System.out.println(ans);
	}

	BufferedReader br;
	PrintWriter out;
	StringTokenizer st;

	String nextToken() throws IOException {
		while (st == null || !st.hasMoreTokens()) {
			String s = br.readLine();
			if (s == null)
				return "-1";
			st = new StringTokenizer(s);
		}
		return st.nextToken();
	}

	int nextInt() throws IOException {
		return Integer.parseInt(nextToken());
	}

	long nextLong() throws IOException {
		return Long.parseLong(nextToken());
	}

	void run() throws IOException {
		br = new BufferedReader(new InputStreamReader(System.in));
		out = new PrintWriter(new OutputStreamWriter(System.out));
		solve();
		br.close();
		out.close();
	}

	public static void main(String[] args) throws IOException {
		new Solution().run();
	}

}
