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.*;
import java.math.BigInteger;
import java.util.*;

import static java.lang.Math.*;

public class Main {
    FastScanner in;
    PrintWriter out;

    static final String FILE = "";


    private static final int MOD = 1_000_000_007;
    private static final int N = 2005;

    int c[][] = new int[N][N];

    void calc() {
        for (int i = 0; i < N; i++) {
            c[i][0] = 1;
            c[i][i] = 1;
            for (int j = 0; j < i; j++) {
                if (i >= 1 && j >= 1) {
                    c[i][j] = c[i - 1][j] + c[i - 1][j - 1];
                    c[i][j] %= MOD;
                }
            }
        }
    }

    public void solve() {
        calc();
        int n = in.nextInt(), m = in.nextInt(), t = in.nextInt();
        long ans = 0;
        for (int i = 0; i <= n; i++) {
            int a = i, b = t - i;
            if (a < 4 || b < 1)
                continue;
            ans += (long)(c[n][a]) * (long)(c[m][b]);
        }
        out.print(ans);
    }

    public void run() {
        if (FILE.equals("")) {
            in = new FastScanner(System.in);
            out = new PrintWriter(System.out);
        } else {
            try {
                in = new FastScanner(new FileInputStream(FILE + ".in"));
                out = new PrintWriter(new FileOutputStream(FILE + ".out"));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
        solve();
        out.close();
    }

    public static void main(String[] args) {
        (new Main()).run();
    }

    class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream is) {
            br = new BufferedReader(new InputStreamReader(is));
        }

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

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }

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

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

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

    public ArrayList<Integer> readIntList(int n) {
        ArrayList<Integer> list = new ArrayList<>();
        for (int i = 0; i < n; i++)
            list.add(in.nextInt());
        return list;
    }

    public ArrayList<String> readStringList(int n) {
        ArrayList<String> list = new ArrayList<>();
        for (int i = 0; i < n; i++)
            list.add(in.next());
        return list;
    }

    class Pair<A extends Comparable<A>, B extends Comparable<B>> implements Comparable<Pair<A, B>> {
        public A a;
        public B b;

        public Pair(A a, B b) {
            this.a = a;
            this.b = b;
        }

        @Override
        public int compareTo(Pair<A, B> o) {
            if (o == null || o.getClass() != getClass())
                return 1;
            int cmp = a.compareTo(o.a);
            if (cmp == 0)
                return b.compareTo(o.b);
            return cmp;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;

            Pair<?, ?> pair = (Pair<?, ?>) o;

            if (a != null ? !a.equals(pair.a) : pair.a != null) return false;
            return !(b != null ? !b.equals(pair.b) : pair.b != null);
        }
    }

    class PairInt extends Pair<Integer, Integer> {
        public PairInt(Integer u, Integer v) {
            super(u, v);
        }
    }

}
