You have two positive integers w and h. Your task is to count the number of rhombi which have the following properties: 

  * Have positive area. 
  * With vertices at integer points. 
  * All vertices of the rhombi are located inside or on the border of the rectangle with vertices at points (0, 0), (w, 0), (w, h), (0, h). In other words, for all vertices (xi, yi) of the rhombus the following conditions should fulfill: 0 ≤ xi ≤ w and 0 ≤ yi ≤ h. 
  * Its diagonals are parallel to the axis. 



Count the number of such rhombi.

Let us remind you that a rhombus is a quadrilateral whose four sides all have the same length.

Input

The first line contains two integers w and h (1 ≤ w, h ≤ 4000) — the rectangle's sizes.

Output

Print a single number — the number of sought rhombi.

Please do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specifier.

Examples

Input

2 2


Output

1


Input

1 2


Output

0

Note

In the first example there exists only one such rhombus. Its vertices are located at points (1, 0), (2, 1), (1, 2), (0, 1).
import java.io.*;
import java.math.BigInteger;
import java.util.*;

public class Main {
    private IO io;
    private int ioMode = -1;
    private String problemName = "";
    private final String mjArgument = "master_j";

    public static void main(String programArguments[]) throws IOException{
        if(programArguments != null && programArguments.length > 0)
            new Main().run(programArguments[0]);
        else
            new Main().run(null);
    }

    private void run(String programArgument) throws IOException {
//         _______________________________________________ _________
//        |   Input Mode     |      Output Mode    | mode | comment |
//        |------------------|---------------------|----- |---------|
//        |   input.txt      |      System.out     |  0   |    mj   |
//        |   System.in      |      System.out     |  1   |  T / CF |
//        |<problemName>.in  |  <problemName>.out  |  2   |         |
//        |   input.txt      |      output.txt     |  3   |    C    |
//        |__________________|_____________________|______|_________|
        long nanoTime = 0;
        if(programArgument != null && programArgument.equals(mjArgument)) // mj
            ioMode = 0;
        else if(System.getProperty("ONLINE_JUDGE") != null) // T / CF
            ioMode = 1;
        else
            ioMode = 2;

        switch(ioMode){
            case -1:
                try{
                    throw new Exception("<ioMode> init failure") ;
                }catch (Exception e){
                    e.printStackTrace();
                }
                return;
            case 0:
                break;
            case 1:
                break;
            case 2:
                if(problemName.length() == 0){
                    try{
                        throw new Exception("<problemName> init failure");
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                    return;
                }
            case 3:
                break;
        }
        io = new IO(ioMode, problemName);
        if(ioMode == 0){
            System.out.println("File output : \n<start>");
            System.out.flush();
            nanoTime = System.nanoTime();
        }
        solve();
        io.flush();
        if(ioMode == 0){
            System.out.println("</start>");
            long t = System.nanoTime() - nanoTime;
            int d3 = 1000000000, d2 = 1000000, d1 = 1000000;
            if(t>=d3)
                System.out.println(t/d3 + "." + t%d3 + " seconds");
            else if(t>=d2)
                System.out.println(t/d2 + "." + t%d2 + " millis");
            else if(t>=d1)
                System.out.println(t/d1 + "." + t%d1 + " millis");
            System.out.flush();
        }
    }

    private void solve() throws IOException {
        int w = io.nI(), h = io.nI();
        long hsum = 0, ans = 0;
        int t = 0;
        for(int i = 1; i<=h; i+=2)
            hsum += h - i;
        for(int i = 1; i<=w; i+=2)
            ans += hsum*(w - i);
        io.wln(ans);
    }//2.2250738585072012e-308

    /**
     * Input-output class
     * @author master_j
     * @version 0.2.1
     */
    @SuppressWarnings("unused")
    private class IO{
        StreamTokenizer in; PrintWriter out; BufferedReader br; Reader reader; Writer writer;
        public IO(int ioMode, String problemName) throws IOException{
            Locale.setDefault(Locale.US);
//         _______________________________________________ _________
//        |   Input Mode     |      Output Mode    | mode | comment |
//        |------------------|---------------------|----- |---------|
//        |   input.txt      |      System.out     |  0   |    mj   |
//        |   System.in      |      System.out     |  1   |  T / CF |
//        |<problemName>.in  |  <problemName>.out  |  2   |         |
//        |   input.txt      |      output.txt     |  3   |    C    |
//        |__________________|_____________________|______|_________|
            switch(ioMode){
                case 0:
                    reader = new FileReader("input.txt");
                    writer = new OutputStreamWriter(System.out);
                    break;
                case 1:
                    reader = new InputStreamReader(System.in);
                    writer = new OutputStreamWriter(System.out);
                    break;
                case 2:
                    reader = new FileReader(problemName + ".in");
                    writer = new FileWriter(problemName + ".out");
                    break;
                case 3:
                    reader = new FileReader("input.txt");
                    writer = new FileWriter("output.txt");
                    break;
            }
            br = new BufferedReader(reader);
            in = new StreamTokenizer(br);
            out = new PrintWriter(writer);
        }
        public void wln(){out.println();}
        public void wln(int arg){out.println(arg);}
        public void wln(long arg){out.println(arg);}
        public void wln(double arg){out.println(arg);}
        public void wln(String arg){out.println(arg);}
        public void wln(boolean arg){out.println(arg);}
        public void wln(char arg){out.println(arg);}
        public void wln(float arg){out.println(arg);}
        public void wln(Object arg){out.println(arg);}
        public void w(int arg){out.print(arg);}
        public void w(long arg){out.print(arg);}
        public void w(double arg){out.print(arg);}
        public void w(String arg){out.print(arg);}
        public void w(boolean arg){out.print(arg);}
        public void w(char arg){out.print(arg);}
        public void w(float arg){out.print(arg);}
        public void w(Object arg){out.print(arg);}
        public void wf(String format, Object...args){out.printf(format, args);}
        public void flush(){out.flush();}
        public int nI() throws IOException {in.nextToken(); return(int)in.nval;}
        public long nL() throws IOException {in.nextToken(); return(long)in.nval;}
        public String nS() throws IOException {in.nextToken(); return in.sval;}
        public double nD() throws IOException {in.nextToken(); return in.nval;}
        public float nF() throws IOException {in.nextToken(); return (float)in.nval;}
        public void wc(char...a){for(char c : a){in.ordinaryChar(c);in.wordChars(c, c);}}
        public void wc(char c1, char c2){in.ordinaryChars(c1, c2); in.wordChars(c1, c2);}
    }
}