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.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Array;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        Reader.init(System.in);
        double h = Reader.nextInt();
        double l = Reader.nextInt();
        double l_h = h*h;
        double l_l = l*l;

        double ans = (l_l-l_h)/(2*h);
        System.out.println(ans);
        /*int n = Reader.nextInt();
        int x= Reader.nextInt();
        int y = Reader.nextInt();
        int[] arr = new int[n];
        for (int i=0; i<n; i++){
            arr[i]  = Reader.nextInt();
        }
        int s_x = 0;
        int s_y = 0;
        int ans= 0;
        boolean done = false;
        int min =Integer.MAX_VALUE;
        for (int i=0; i<n; i++){
            int val = arr[i];
            if (s_x<x){
                if (val<=min){
                    min=val;
                }
                s_x++;
            }
            else if (s_x>x){
                if (val<min){
                    ans =i;
                    for (int j=i; j<i+s_y; j++){
                        int val1= arr[j];
                        if (val1<min){
                            break;
                        }
                        else if (j==i+s_y-1){
                            ans=i;
                            done=true;
                        }
                    }
                }
                else {
                    s_x=0;

                }

            }



        }*/
    }
}

class solu{

   /* public long func(int[] arr, int k){
        long ans = 0;
        if (arr.length==k||arr.length==1){
            return 0;
        }
        int set = arr[0];
        int size=1;
        ArrayList<Integer> lis = new ArrayList<>();
        for (int i =1; i<arr.length; i++){
            int val =arr[i];
            if (val==set){
                size=size+1;
            }
            else {
                lis.add(size);
                set=val;
                size=0;
            }
        }


        return ans;
    }*/
   public String func2(int[] s_arr, int[] arr){
        int max = s_arr[s_arr.length-1];
        int max_ind=0;

        for (int i=0; i<arr.length; i++){
            int val =arr[i];
            if (val==max){
                max_ind=i;
            }
        }
        for (int i=arr.length-2; i>=0; i--){
            int val = s_arr[i];
            int index= Arrays.binarySearch(arr, val);
            System.out.println();
            System.out.println(index);
            if (index+1<arr.length-1&&index-1>0){
                if (arr[index-1]==max){
                    arr[index]=max;
                }
                else if (arr[index+1]==max){
                    arr[index]=max;
                }
                else {
                    return "NO";
                }
            }
            else {
                if (index-1<0){
                    if (arr[index+1]==max){
                        arr[index]=max;
                    }
                    else {
                        return "NO";
                    }
                }
                if (index+1>=arr.length){
                    if (arr[index-1]==max){
                        arr[index]=max;
                    }
                    else {
                        return "NO";
                    }
                }
            }
        }
        return "YES";
   }
}








/** Class for buffered reading int and double values */
class Reader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /** call this method to initialize reader for InputStream */
    static void init(InputStream input) {
        reader = new BufferedReader(
                new InputStreamReader(input) );
        tokenizer = new StringTokenizer("");
    }

    /** get next word */
    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                    reader.readLine() );
        }
        return tokenizer.nextToken();
    }

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

    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }
    static long nextLong() throws IOException {
        return Long.parseLong( next() );
    }
}