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 codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
	   Scanner sc=new Scanner(System.in);
	   int n=sc.nextInt();
	   int m=sc.nextInt();
	   int t=sc.nextInt();
	   long a[][]=new long[31][31];
	   for(int i=1;i<31;i++){a[i][0]=1;}
	   a[1][1]=1;
	   for(int i=2;i<31;i++){
	       for(int j=1;j<=i;j++){
	           a[i][j]=a[i-1][j-1]+a[i-1][j];
	           //System.out.println(i+" "+j+" "+a[i][j]);
	       }
	   }
	   
	   long ans=0;int z=4;
	   while(z<=n&&z<t){
	       if(t-z<=m)ans+=a[n][z]*a[m][t-z];
	       //System.out.println(ans);
	       z++;
	   }
	   System.out.println(ans);
	}
}
