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
// practice with rainboy
import java.io.*;
import java.util.*;

public class CF131C extends PrintWriter {
	CF131C() { super(System.out, true); }
	Scanner sc = new Scanner(System.in);
	public static void main(String[] $) {
		CF131C o = new CF131C(); o.main(); o.flush();
	}

	static final int N = 30;
	void main() {
		long[][] ch = new long[N + 1][N + 1];
		ch[0][0] = 1;
		for (int i = 1; i <= N; i++) {
			ch[i][0] = 1;
			for (int j = 1; j <= i; j++)
				ch[i][j] = ch[i - 1][j] + ch[i - 1][j - 1];
		}
		int n = sc.nextInt();
		int m = sc.nextInt();
		int t = sc.nextInt();
		long ans = 0;
		for (int b = 4; b <= n && b < t; b++) {
			int g = t - b;
			if (g <= m)
				ans += ch[n][b] * ch[m][g];
		}
		println(ans);
	}
}
