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


/* Name of the class has to be "Main" only if the class is public. */
public class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int m=sc.nextInt();
		int t=sc.nextInt();
		long[][] arr=new long[61][61];
		for(int i =0; i<61;i++){
			for(int j=0;j<=i;j++){
				if(j==0||j==i){
					arr[i][j]=1;
				}else{
					arr[i][j]=arr[i-1][j]+arr[i-1][j-1];
				}
			}
		}
		long ans=0;
		ans+=arr[m+n][t]-(arr[n][t]*arr[m][0]);
		for(int i=0;i<=3;i++){
			ans-= arr[n][i]*arr[m][t-i];
		}
		System.out.println(ans);
	}
}