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.*;
import java.lang.*;
import java.io.*;
import java.math.*;

public class Main {
    
    static long C(long n, long k) {
        long x = 1;
        for (long i = 0; i < k; i++) {
            x = x * (n - i) / (i + 1);
        }
        return x;
    }
    //---------------------------------------------------------------------------
    public static void main(String[] args) throws Exception {
        InputReader in = new InputReader(System.in);
        PrintWriter out = new PrintWriter(System.out);
        //-----------------------------------------------------------------------
        long n = in.nextLong();
        long m = in.nextLong();
        long t = in.nextLong();
        long ans = C(n + m, t) - C(n, 1) * C(m, t - 1) - C(n, 2) * C(m, t - 2) - C(n, 3) * C(m, t - 3) - C(n, t) - C(m, t);
        out.println(ans);
        //-----------------------------------------------------------------------
        out.close();
    }

    //---------------------------------------------------------------------------
    static class Pair implements Comparator {

        int first, second;

        public Pair() {

        }

        public Pair(int f, int s) {
            this.first = f;
            this.second = s;
        }

        @Override
        public int compare(Object o1, Object o2) {
            Pair p1 = (Pair) o1;
            Pair p2 = (Pair) o2;
            int ret = Integer.compare(p1.first, p2.first);
            if (ret == 0) {
                ret = Integer.compare(p1.second, p2.second);
            }
            return ret;
        }
    }

    static class InputReader {

        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

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

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public char[] nextCharArray() {
            return next().toCharArray();
        }

        public boolean hasNext() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    String s = reader.readLine();
                    if (s == null) {
                        return false;
                    }
                    tokenizer = new StringTokenizer(s);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return true;
        }

        public void skipLine() {
            try {
                tokenizer = null;
                reader.readLine();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }
}
