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.Scanner;
public class Main {

    public static void main(String[] args) {
	    Scanner s=  new Scanner(System.in);
	    int n = s.nextInt();
	    int m = s.nextInt();
	    int t = s.nextInt();
	    long res =0;
	    for(int boy =4;t-boy>=1;boy++){
	        res += c(n,boy) * c(m,t-boy);
        }
        System.out.println(res);
    }
    public static long c(int n,int r){
        long result =1;
        for(int i=0;i<r;i++){
            result = result *(n-i)/(i+1);
        }
        return result;
    }
}