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.*;

public class Theater {
	public static final boolean debug = false;
	public static int M = 10^9+7; 


	public static void main (String [] args) {
		Scanner input = new Scanner (System.in);

		int boys = input.nextInt();
		int girls = input.nextInt();
		int t = input.nextInt();
		long finalCount = 0;

		int maxN = t + boys + girls;
		int maxR = t + boys + girls;
//		System.out.println(maxN);
		long[][] table = new long[maxN+1][maxR+1];

		for (int n = 0; n < table.length; n++) {
			table[n][0] = 1;
			table[n][n] = 1;
			for (int c = 1; c < n; c++) {
				table[n][c] = table[n-1][c]+ table[n-1][c-1];
			}
		}

		for (int i = 4; i < t; i++) {
			if (t-i >= 1) {
				if (debug) {
					System.out.println(boys + " choose " + i);
					System.out.println(table[boys][i]);
					System.out.println(girls+ " choose " + (t-i));
					System.out.println(table[girls][t-i]);
				}
				finalCount += table[boys][i] * table[girls][t-i]; 
			}
		}

		System.out.println(finalCount);
	}
}
