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.*;
import java.math.*;

public class Main{

  long n,m,t;

  public void run(){
    Scanner in = new Scanner(System.in);
    n = in.nextLong();
    m = in.nextLong();
    t = in.nextLong();
    BigInteger ans = new BigInteger("0");
    for(long i=4;i<=n;i++){
      long x = t - i;
      if (x > 0){
        ans = ans.add(C(i, n).multiply(C(x, m)));
      }
    }
    System.out.println(ans);
  }
  
  private BigInteger C(long x, long y){
    BigInteger ret = new BigInteger("1");
    for(int i=1;i<=y;i++){
      ret = ret.multiply(new BigInteger(Integer.toString(i)));
    }
    for(int i=1;i<=x;i++){
      ret = ret.divide(new BigInteger(Integer.toString(i)));
    }
    for(int i=1;i<=y-x;i++){
      ret = ret.divide(new BigInteger(Integer.toString(i)));
    }
    
    return ret;
  }

  public static void main(String argsp[]){
    new Main().run();
  }
}
