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
//package codeforces.practice.div2c;

import java.io.*;
import java.util.*;

public class CF131C {
    private static int UNVISITED = 0;
    private static int VISITING = -1;
    private static int VISITED = 1;

    public static void main(String[] args) {
//        try {
//            FastScanner in = new FastScanner(new FileInputStream("src/input.in"));
//            PrintWriter out = new PrintWriter(new FileOutputStream("src/output.out"));

        FastScanner in = new FastScanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

            solve(1, in, out);

//        } catch (IOException e) {
//            e.printStackTrace();
//        }
    }

    private static void solve(int q, FastScanner in, PrintWriter out) {
        for (int qq = 0; qq < q; qq++) {
            int n = in.nextInt(), m = in.nextInt(), t = in.nextInt();
            long ans = 0;
            long[] cm = new long[Math.min(m, t - 4) + 1];
            long[] cn = new long[Math.min(n, t - 1) + 1];
            cm[0] = 1;
            for(int i = 1; i < cm.length; i++) {
                cm[i] = cm[i - 1] * (m - i + 1) / i;
            }
            cn[0] = 1;
            for(int i = 1; i < cn.length; i++) {
                cn[i] = cn[i - 1] * (n - i + 1) / i;
            }
            for(int i = 4; i <= Math.min(n, t - 1); i++) {
                ans += (t - i <= m ? cn[i] * cm[t - i] : 0);
            }
            out.println(ans);
        }
        out.close();
    }

    private static long modularAdd(long a, long b, int mod) {
        long sum = a + b;
        if (sum >= mod) {
            sum -= mod;
        }
        return sum;
    }

    private static long modularSubtract(long a, long b, int mod) {
        long diff = a - b;
        if (diff < 0) {
            diff += mod;
        }
        return diff;
    }

    private static Stack<Integer> topologicalSort(Set<Integer>[] g) {
        Stack<Integer> stack = new Stack<>();
        int[] state = new int[g.length];

        for (int node = 0; node < g.length; node++) {
            if (!topoSortHelper(g, stack, state, node)) {
                return null;
            }
        }
        return stack;
    }

    private static boolean topoSortHelper(Set<Integer>[] g, Stack<Integer> stack, int[] state, int currNode) {
        if (state[currNode] == VISITED) {
            return true;
        } else if (state[currNode] == VISITING) {
            return false;
        }
        state[currNode] = VISITING;
        for (int neighbor : g[currNode]) {
            if (!topoSortHelper(g, stack, state, neighbor)) {
                return false;
            }
        }
        state[currNode] = VISITED;
        stack.push(currNode);
        return true;
    }

    static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        FastScanner(InputStream stream) {
            try {
                br = new BufferedReader(new InputStreamReader(stream));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

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

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

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

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

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


