Problem: While sailing on a boat, Inessa noticed a beautiful water lily flower above the lake's surface. She came closer and it turned out that the lily was exactly H centimeters above the water surface. Inessa grabbed the flower and sailed the distance of L centimeters. Exactly at this point the flower touched the water surface.

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Suppose that the lily grows at some point A on the lake bottom, and its stem is always a straight segment with one endpoint at point A. Also suppose that initially the flower was exactly above the point A, i.e. its stem was vertical. Can you determine the depth of the lake at point A?

Input

The only line contains two integers H and L (1 ≤ H < L ≤ 10^{6}).

Output

Print a single number — the depth of the lake at point A. The absolute or relative error should not exceed 10^{-6}.

Formally, let your answer be A, and the jury's answer be B. Your answer is accepted if and only if \frac{|A - B|}{max{(1, |B|)}} ≤ 10^{-6}.

Examples

Input


1 2


Output


1.5000000000000


Input


3 5


Output


2.6666666666667

Solution (in JAVA):

Solution:
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.util.StringTokenizer;
    import java.io.PrintWriter;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.HashMap;
    import java.util.TreeMap;
    import java.util.Map;
    import java.util.Arrays;
    import java.util.Set;
    import java.util.HashSet;
    import java.util.Iterator;
    import java.util.Collections;
    import java.util.LinkedList;
    import java.util.Stack;
    
    /*
     *
     *  @author Riddle
     *
     */

    public final class WaterLily
    {
        final static long MOD = (long)1e9+7;
        static class FastReader
        {
            BufferedReader br;
            StringTokenizer st;
     
            public FastReader()
            {
                br = new BufferedReader(new
                         InputStreamReader(System.in));
            }
     
            String next()
            {
                while (st == null || !st.hasMoreElements())
                {
                    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;
            }
        }

        public static void main(String args[])
        {
            FastReader reader = new FastReader();
            PrintWriter out = new PrintWriter(System.out);
            double h = reader.nextDouble();
            double l = reader.nextDouble();
            solve(h,l);
            out.flush();        
            out.close();
        }

        public static void solve(double h, double l)
        {
            double x = Math.pow(10, 6);
            double result = (l*l*x-h*h*x)/(2*h*x);
            System.out.printf("%.12f", result);

        }
    }