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.awt.Point;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
import java.*;
import java.util.PriorityQueue;

public class Main {
	static long[][] memo = new long[35][];

	public static void main(String args[]) throws NumberFormatException,
			IOException {
		Scanner in = new Scanner(System.in);
		for (int i = 0; i < 35; i++) {
			memo[i] = new long[i + 1];
			memo[i][0] = 1;
			memo[i][memo[i].length - 1] = 1;
		}
		for (int i = 1; i < 35; i++) {
			for (int j = 1; j < memo[i].length - 1; j++) {
				memo[i][j] = memo[i - 1][j - 1] + memo[i - 1][j];
			}
		}
		int n = in.nextInt();
		int m = in.nextInt();
		int t = in.nextInt();
		long sum = 0;
		for (int i = 4; i <= n; i++) {

			for (int j = 1; j <= m; j++) {
				if (i + j == t)
					sum = sum + (memo[n][i] * memo[m][j]);

			}

		}
		System.out.println(sum);
	}
}

