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.util.StringTokenizer;


public class Task131C {

    public static void main(String[] args) throws IOException {
        InputScanner is = new InputScanner();
        int n = is.nextInt();
        int m = is.nextInt();
        int t = is.nextInt();

        long val = 0;
        for (int i = 4; i <=n ; i++) {
            int g = t - i;
            if (g>=1) val += N(n, i) * N(m, g);
        }
        System.out.println(val);
    }

    public static long N(int n, int k) {
        long r = 1;
        for (int i = 1; i <= k; i++) r = r * (n - i + 1) / i;
        return r;
    }


    static class InputScanner {
        BufferedReader br;
        StringTokenizer st;

        public InputScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public String next() throws IOException {
            if (st == null || !st.hasMoreTokens()) {
                String line = br.readLine();
                st = new StringTokenizer(line);
            }
            return st.nextToken();
        }

        public int nextInt() throws IOException {
            String next = next();
            return Integer.parseInt(next);
        }

        public long nextLong() throws IOException {
            String next = next();
            return Long.parseLong(next);
        }
    }
}
