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 n = scan.nextInt();
        int m = scan.nextInt();
        int t = scan.nextInt();
        
        long ans =0;
        for(int i=4;i<t;i++)
        {
            ans += count(n,i)*count(m, t-i);
        }
        System.out.println(ans);
    }
    public static long count(int n , int k)
    {
        long res=1;
        for(int i=0 ;i<k ;i++)
        {
            res *= (n-i);
            res /= (i+1);
        }
        return res;
    }
}