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 C {

    static long ncr(int n, int r) {
        long res = 1;
        r = Math.min(r, n - r);
        for (long i = 0; i < r; i++)
            res = (res * (n - i)) / (i + 1);
        return res;
    }

    public static void main(String[] args) throws Throwable {
        Scanner myScanner = new Scanner(System.in);
        int b = myScanner.nextInt(), g = myScanner.nextInt(), all = myScanner
                .nextInt(), gg;
        long res = 0;
        for (int bb = 4; bb <= b; bb++) {
            gg = all - bb;
            if (gg>0&&gg <= g)
                res+=(ncr(b, bb)*ncr(g, gg));
        }
        System.out.println(res);
    }
}
