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

public class ContestC implements Runnable {

    
    public void run() {
        int B = nextInt();
        int G = nextInt();
        int t = nextInt();
        
        long ans = 0;
        
        for(int i=1; i<t; i++){
            if(t-i < 4) break;
            if(i>G) break;
            ans+= (long) C(G,i)*(C(B,t-i));
            
            
        }
        
        System.out.println(ans);
        
        
        
        
        
        

        
        
        
        
//      -----------------------------------------------------------------------------------

        out.close();
        System.exit(0);
    }
    public  long C  (int a, int b){
        long[][] combin = new long [65][65];
        for(int i=0; i<31; i++){
            combin[i][0] = 1;
        }
        for(int i=1; i<31; i++){
            for(int j=1; j<=i;j++){
                combin[i][j] = combin[i-1][j] + combin[i-1][j-1];
            }
        }
        
        return combin[a][b];
    }
    
    private static boolean fileIOMode;
    private static String problemName = "xxx";
    private static BufferedReader in;
    private static PrintWriter out;
    private static StringTokenizer tokenizer;

    public static void main(String[] args) throws Exception {
        fileIOMode = false;
        if (fileIOMode) {
            in = new BufferedReader(new FileReader(problemName + ".in"));
            out = new PrintWriter(problemName + ".out");
        } else {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        }
        tokenizer = new StringTokenizer("");

        new Thread(new ContestC()).start();
    }

    private static String nextLine() {
        try {
            return in.readLine();
        } catch (IOException e) {
            return null;
        }
    }

    private static String nextToken() {
        while (!tokenizer.hasMoreTokens()) {
            String str = nextLine();
            if(str==null) return null;
            tokenizer = new StringTokenizer(str);
        }
        return tokenizer.nextToken();
    }

    private static int nextInt() {
        return Integer.parseInt(nextToken());
    }

    private static long nextLong() {
        return Long.parseLong(nextToken());
    }

    private static double nextDouble() {
        return Double.parseDouble(nextToken());
    }

    private static BigInteger nextBigInteger() {
        return new BigInteger(nextToken());
    }

    private static void print(Object o) {
        if (fileIOMode) {
            System.out.print(o);
        }
        out.print(o);
    }

    private static void println(Object o) {
        if (fileIOMode) {
            System.out.println(o);
        }
        out.println(o);
    }

    private static void printf(String s, Object... o) {
        if (fileIOMode) {
            System.out.printf(s, o);
        }
        out.printf(s, o);
    }
}


