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;

public class C {

	/**
	 * @param args
	 */
	static void combiation(int n,int m)
	{
		com = new long[n+1][m+1];
		for(int i=0;i<m;i++)
			com[i][0] = 1;
		for(int i=1;i<=n;i++)
			for(int j=1;j<=m;j++)
				com[i][j] = com[i-1][j] + com[i-1][j-1];
	}
	static long[][] com;
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		combiation(100,100);
		Scanner scan = new Scanner(System.in);
		int n  = scan.nextInt();
		int m  = scan.nextInt();
		int t  = scan.nextInt();
		long c = 0;
		for(int i = 4 ; i  <= n ; i ++)
		{
			int mm = t-i;
			if(mm > 0){
				c += com[n][i]*com[m][mm];
			}
		}
		System.out.println(c);
	}
}
