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.*;
public class Main
{
  public static void main(String[] args)
  {
    Scanner scan = new Scanner(System.in);
    int b = scan.nextInt();
    int g = scan.nextInt();
    int t = scan.nextInt();
    Long[][] choose = new Long[61][61];
    for (int i = 0; i < 61; i++)
    {
      for (int j = 0 ; j < 61; j++)
      {
        choose[i][j] = 0L;
      }
    }
    for (int i = 0; i < 61; i++)
    {
      choose[i][0] = 1L;
      choose[i][i] = 1L;
    }
    for (int i = 1; i < 61; i++)
    {
      for (int j = 1; j < i; j++)
      {
        choose[i][j] = choose[i - 1][j - 1] + choose[i - 1][j];
      }
    }
    Long count = choose[b + g][t];
    count -= choose[b][t];
    for (int i = 0; i < 4; i++)
      count -= choose[g][t - i] * choose[b][i];
    System.out.println(count);
  }
}