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.math.*;

public class Main {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int m = sc.nextInt();
int t = sc.nextInt();
long total = 0;
for (int g=1; g<=t-4; g++){
  int b = t-g;
  long a = C(n,b);
  long aa = C(m,g);
  total+=a*aa;
}
System.out.println(total);

}

private static long C(int a, int b){
  return fact(a).divide(fact(b)).divide(fact(a-b)).longValue();
}

private static BigInteger fact(int a){
  BigInteger bi = new BigInteger("1");
  for (Integer i=2; i<=a; i++){
    bi = bi.multiply(new BigInteger(i.toString()));
  }
  return bi;
}
}
