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 C131 {
    public static long pas(int a, int b, long A[][]) {
        if (A[a][b] != 0)
            return A[a][b];
        if (a == 1 || b == 0 || a == b) {
            A[a][b] = 1;
            return 1;
        }
        long x = pas(a - 1, b, A) + pas(a - 1, b - 1, A);
        A[a][b] = x;
        return x;
    }

    public static void main(String[] args) {
        {
            Scanner sc = new Scanner(System.in);
            int b = sc.nextInt(), g = sc.nextInt(), t = sc.nextInt();
            long[][] A = new long[50][50];
            long ans = 0;
            int boys = t - 1;
            int girls = 1;
            while (true) {
                if (boys > b) {
                    boys--;
                    girls++;
                } else {
                    break;
                }
            }
            while (boys + girls == t && boys >= 4 && girls <= g) {
                ans += pas(b, boys, A) * pas(g, girls, A);
                boys--;
                girls++;
            }
            System.out.println(ans);
        }
    }
}
