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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class Solution {

    private final static FastReader in = new FastReader();
    private static final PrintWriter out = new PrintWriter(System.out);


    public static long solve(int n, int m, int k) {
        long ans = 0;
        for (int i = 4; i <= n && k - i > 0; i++) {
            ans += Db(n, i) * Db(m, k - i);
        }
        return ans;
    }

    static long Db(int n, int k) {
        long ans = 1;
        for (int i = n, ind = 1; i > n - k; i--) {
            ans *= i;
            ans /= ind++;
        }
        return ans;
    }

    public static void main(String[] args) {
        int n = in.nextInt();
        int m = in.nextInt();
        int t = in.nextInt();
        out.println(solve(n, m, t));
        out.close();
    }

    private static final class FastReader {
        private static BufferedReader BF;
        private static StringTokenizer ST;

        public FastReader() {
            BF = new BufferedReader(new InputStreamReader(System.in));
            ST = null;

        }


        public final String next() {
            while (ST == null || !ST.hasMoreTokens()) {
                try {
                    ST = new StringTokenizer(BF.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return ST.nextToken();

        }

        final int nextInt() {
            return Integer.parseInt(next());
        }

        final long nextLong() {
            return Long.parseLong(next());
        }
    }


}