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
//package srms;

import java.util.Scanner;

public class theatre {
    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 ans = 0;
        for (int man = t - 1; man >= 4; --man) {
            int woman = t - man;
            if (woman < 1) break;
            ans += C(n, man) * C(m, woman);
        }
        System.out.print(ans);
    }

    public static long C(int n, int k) {
        double res = 1;
        for (int i = 1; i <= k; ++i)
            res = res * (n - k + i) / i;
        return (long) (res + 0.01);
    }

}