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.*;
import java.math.*;
/* Name of the class has to be "Main" only if the class is public. */
public class Ideone
{
	
	public static long l[][] = new long[1001][1001]; 
	
	public static void initialize() 
    { 
  
        // 0C0 = 1 
        l[0][0] = 1; 
        for (int i = 1; i < 1001; i++) { 
            // Set every nCr = 1 where r = 0 
            l[i][0] = 1; 
            for (int j = 1; j < i + 1; j++) { 
  
                // Value for the current cell of Pascal's triangle 
                l[i][j] = (l[i - 1][j - 1] + l[i - 1][j]); 
            } 
        } 
    } 
  
	
	 public static long nCr(int n, int r) 
    { 
        // Return nCr 
        return l[n][r]; 
    } 
	
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner in=new Scanner(System.in);
		int n=in.nextInt();
		int m=in.nextInt();
		int t=in.nextInt();
		initialize(); 
		
		long sum=0;
	for(int i=4;i<=t-1;i++){
		int b = i, g = t-i;
		sum = (sum + l[n][b]*l[m][g]);
	}
		
      System.out.println(sum);		
	}
}