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.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

public class Solution {
    static long[][] memo;

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        long n = in.nextLong();
        long m = in.nextLong();
        long t = in.nextLong();
        memo = new long[40][40];
        for (int i = 0; i < 40; i++)
            Arrays.fill(memo[i], Long.MIN_VALUE);

        long ans = 0;

        for (long i = Math.max(4, t - m); i <= Math.min(t - 1, n); i++)
            ans += C(n, i) * C(m, t - i);

        out.println(ans);
        out.close();
    }

    private static long C(long n, long k) {
        if (n == 1)
            return k == 1 ? 1 : 0;
        if (k == 1)
            return n;
        if (k <= 0)
            return 0;
        if (memo[(int) n][(int) k] != Long.MIN_VALUE)
            return memo[(int) n][(int) k];
        long ans = C(n - 1, k - 1) + C(n - 1, k);
        memo[(int) n][(int) k] = ans;
        return ans;
    }
}
