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 Main {
    static int M, N, T;
    static long[][] memo;

    static long[][] a;

    public static long combineDfs(int n, int r) {
        if (r == 0 || n == r)
            return 1;
        if (a[n - 1][r - 1] == 0)
            a[n - 1][r - 1] = combineDfs(n - 1, r - 1);
        if (a[n - 1][r] == 0)
            a[n - 1][r] = combineDfs(n - 1, r);

        return a[n - 1][r - 1] + a[n - 1][r];
    }

    public static long getWays(int n, int m, int t) {
        if (memo[n][m] != -1)
            return 0;

        if (n == N + 1 || m == M + 1)
            return memo[n][m] = 0;
        if (t == T) {
            if (n >= 4 && m >= 1) {
                return memo[n][m] = combineDfs(N, n) * combineDfs(M, m);
            } else
                return memo[n][m] = 0;
        }
        return (memo[n][m] = (getWays(n + 1, m, t + 1) + getWays(n, m + 1,
                t + 1)));

    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        N = in.nextInt();
        M = in.nextInt();
        T = in.nextInt();

        a = new long[32][32];
        memo = new long[N + 2][M + 2];
        for (int i = 0; i < memo.length; i++)
            for (int j = 0; j < memo[0].length; j++)
                memo[i][j] = -1;
        System.out.println(getWays(0, 0, 0));

    }

}
