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 Theatre {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        long n, m, t, i, ans = 0;
        n = in.nextInt();
        m = in.nextInt();
        t = in.nextInt();
        for(i=4; i<t; i++){
            ans+= func(n,i)*func(m, t-i);
        }
        System.out.println(ans);
    }
    
    static long func(long n, long m){
        long i, r = 1;
        for(i=1; i<=m; i++){
            r *= n-i+1;
            r /= i;
        }
        return r;
    }
}