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.

<image>

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.*;
import java.util.*;
import java.lang.*;
import java.math.*;
public class Main extends Thread  {
    boolean[] prime;
    FastScanner sc;
    PrintWriter pw;
    MathF mf;
    final class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner() {
            try {
                br = new BufferedReader(new InputStreamReader(System.in));
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        public long nlo() {
            return Long.parseLong(next());
        }

        public String next() {
            if (st.hasMoreTokens()) return st.nextToken();
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return st.nextToken();
        }

        public int ni() {
            return Integer.parseInt(next());
        }

        public String nli() {
            String line = "";
            if (st.hasMoreTokens()) line = st.nextToken();
            else try {
                return br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            while (st.hasMoreTokens()) line += " " + st.nextToken();
            return line;
        }

        public double nd() {
            return Double.parseDouble(next());
        }
    }
    final class MathF {
        long grtdiv(long x)
        {
            if(isPrime(x))
                return 1;
            else
            {
                long ans=0;
                long y=(long)Math.sqrt(x)+1;
                for(;y>=2;y--)
                {
                    if(x%y==0)
                        ans=Math.max(ans,Math.max(y,x/y));
                }
                return ans;
            }
        }
        boolean isPrime(long x)
        {
            for(int i=2;i*i<=x;i++)
            {
                if(x%i==0)
                {
                    return false;
                }
            }
            return true;
        }
        long[][] mul(long[][] arr,long[][] brr,int a,int b,int c,int d)
        {
            long[][] crr=new long[a][d];
            for(int i=0;i<a;i++)
            {
                for(int j=0;j<d;j++)
                {
                    for(int k=0;k<b;k++)
                    {
                        crr[i][j]+=(((arr[i][k]%1000000007)*(brr[k][j]%1000000007))%1000000007);
                    }
                }
            }
            return crr;
        }
        int sod(long a)
        {
            int ans=0;
            while(a!=0)
            {
                ans+=(a%10);
                a=a/10;
            }
            return ans;
        }
        long pow(long a,long b)
        {
            if(b==0)
                return 1;
            else
            {
                long x=pow(a,b/2);
                if(b%2==1)
                    return (x*x*a);
                else
                    return (x*x);
            }
        }
        public  long gcd(long a, long b) {
            return (b == 0 ? a : gcd(b, a % b));
        }
        public long exponent(long a,long b)
        {
            if(b==0)
                return 1;
            else
            {
                long x=exponent(a,b/2);
                x*=x;
                if(b%2==1)
                    x*=a;
                return x;
            }
        }
        public  int nod(long x) {
            int i = 0;
            while (x != 0) {
                i++;
                x = x / 10;
            }
            return i;
        }

        public  int nob(long x) {
            if(x==0)
                return 1;
            return (int) Math.floor(Math.log(x) / Math.log(2)) + 1;
        }

        public int[] FastradixSort(int[] f) {
            int[] to = new int[f.length];
            {
                int[] b = new int[65537];
                for (int i = 0; i < f.length; i++) b[1 + (f[i] & 0xffff)]++;
                for (int i = 1; i <= 65536; i++) b[i] += b[i - 1];
                for (int i = 0; i < f.length; i++) to[b[f[i] & 0xffff]++] = f[i];
                int[] d = f;
                f = to;
                to = d;
            }
            {
                int[] b = new int[65537];
                for (int i = 0; i < f.length; i++) b[1 + (f[i] >>> 16)]++;
                for (int i = 1; i <= 65536; i++) b[i] += b[i - 1];
                for (int i = 0; i < f.length; i++) to[b[f[i] >>> 16]++] = f[i];
                int[] d = f;
                f = to;
                to = d;
            }
            return f;
        }

        public  void Primesieve(int n) {
            prime=new boolean[n];
            for (int i = 0; i < n; i++)
                prime[i] = true;
            for (int p = 3; p * p < n; p+=2) {
                if (prime[p] == true) {
                    for (int i = p * p; i < n; i += p)
                        prime[i] = false;
                }
            }
        }
    }
    public Main(ThreadGroup t,Runnable r,String s,long d )
    {
        super(t,r,s,d);
    }
    public void run()
    {
        sc=new FastScanner();
        pw=new PrintWriter(System.out);
        mf=new MathF();
        solve();
        pw.flush();
        pw.close();
    }
    public static void main(String[] args)
    {
        new Main(null,null,"",1<<20).start();
    }

    /////////////------------------------------------/////////////
    /////////////------------------------------------/////////////
    ////////////------------------MAIN-LOGIC---------/////////////
    ////////////-------------------------------------/////////////
    ///////////--------------------------------------/////////////


    public void solve(){
        int t=1;
        while(t-->0) {
         int h=sc.ni();
         int l=sc.ni();
         double a=Double.valueOf(h);
         double b=Double.valueOf(l);
         double c=Double.valueOf(2);
         double d=(b*b);
         d-=(a*a);
         d/=2;
         d/=a;
         pw.print(d);
        }
    }
}