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.io.*;
public class Main{
  static long C(int n, int m) {
    long result = 1;
    for (int i = 0; i < m; ++i)
    {
        result *= (n - i);
        result /= (i + 1);
    }
    return result;
  }
  public static void main(String []args)throws IOException{
    BufferedReader br  = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));
    StringTokenizer st ;
    st = new StringTokenizer(br.readLine());
    int a = Integer.parseInt(st.nextToken());
    int b = Integer.parseInt(st.nextToken());
    int t = Integer.parseInt(st.nextToken());
//    if(a+b==t)
//      System.out.println("1");
//    else{
      long pairs = 0 ;
      for(int i = 4 ; i < t ; i++){
        pairs+= C(a,i)*C(b,t-i);
      }
      System.out.println(pairs);
  }
}