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;

// http://codeforces.com/problemset/problem/131/C
public class WorldTheatre {

	public static void main(String[] args) {
		int len = 31;
		long[][] dp = new long[len][len];

		for (int i = 0; i < len; i++) {
			dp[i][0] = 1;
		}

		for (int i = 0; i < len; i++) {
			dp[i][i] = 1;
		}

		for (int i = 1; i < len; i++) {
			for (int j = 1; j < len; j++) {
				dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j];
			}
		}

		try (Scanner in = new Scanner(System.in)) {
			int n = in.nextInt();
			int m = in.nextInt();
			int t = in.nextInt();
			long counter = 0;
			int boys = 4;

			while (boys < t && boys <= n) {
				int girls = t - boys;

				if (girls <= m) {
					counter += dp[n][boys] * dp[m][t - boys];
				}
				++boys;
			}
			System.out.println(counter);
		}
	}
}