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
//package practice;

import java.util.*;
public class CF {

	/**
	 * @param args
	 */
	static int boy,girl,target;
	static long[][][] dp=new long[100][100][100];
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		boy=sc.nextInt();
		girl=sc.nextInt();
		target=sc.nextInt();
		for(int i=0;i<100;i++)
			for(int j=0;j<100;j++)
				for(int h=0;h<100;h++)
					dp[i][j][h]=-1;
		System.out.println(count(1,0,0,target));

	}
	
	
	
	static long count(int index,int boys,int girls,int rem)
	{
		if(rem==0&&girls>=1&&boys>=4) return 1;
		if(index==boy+girl+1) return 0;
		if(dp[index][boys][girls]!=-1) return dp[index][boys][girls];
		if(index>boy)
		{
			long take   =   (rem>0)?count(index+1,boys,girls+1,rem-1):0;
			long leave  =   count(index+1,boys,girls,rem);
			return dp[index][boys][girls]=take+leave;
		}
		else
		{
			long take   = (rem>1)?count(index+1,boys+1,girls,rem-1):0;
			long leave  = count(index+1,boys,girls,rem);
			return dp[index][boys][girls]=take+leave;
		}
	}

}
