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

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.math.*;
/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
 
 
 
public class Main {
	
	static int k;
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader();
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }
 
    static class TaskC {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
        	
        	double h=in.nextInt();
        	double l=in.nextInt();
        	System.out.println((l*l - h*h)/(2*h));
        	
        }
        
    }
   
    		
    	
    	
   
    	
    
    static long sumAP(long a, long d, long n) 
    { 
    	int mod = 1000000007;
    	long sum = (n*modInverse(2,mod)%mod) ; 
    	long temp = (n-1)%mod;
    	temp+= 2*a;
    	temp%=mod;
    	temp = (temp * d)%mod;
    	sum = (sum*temp)%mod;	
        return (long) sum; 
    }
    public static long digSum(long number) {
        long digitSum = 0;
 
        while (number > 0) {
            digitSum = digitSum + (number % 10);
            number = number / 10;
        }
 
        return digitSum;
    }
    
    static int comb(int n , int r)
	{
		if( r== 0 || n == r)
			return 1;
		else
			return comb(n-1,r)+comb(n-1,r-1);
	}
    public static long fexp(long x, long y, long p) {
    	long res = 1;      
        
       
        x = x % p;  
      
        while (y > 0) 
        { 
         
            if((y & 1)==1) 
                res = (res * x) % p; 
      
          
            y = y >> 1;  
            x = (x * x) % p;  
        } 
        return res; 
    	
    }
    static int gcd(int a, int b) 
    { 
        if (b == 0) 
            return a; 
        return gcd(b, a % b);  
          
    } 
    static long mod(String num, int a) 
    { 
          
        long res = 0; 
  
 
        for (int i = 0; i < num.length(); i++) 
            res = (res * 10 + (int)num.charAt(i) 
                                     - '0') % a; 
  
        return res; 
    } 
        
    
 
    static class InputReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public InputReader()
        {
            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 sort(long[] a, int low, int high) 
    {
        int N = high - low;         
        if (N <= 1) 
            return; 
        int mid = low + N/2; 
        // recursively sort 
        sort(a, low, mid); 
        sort(a, mid, high); 
        // merge two sorted subarrays
        long[] temp = new long[N];
        int i = low, j = mid;
        for (int k = 0; k < N; k++) 
        {
            if (i == mid)  
                temp[k] = a[j++];
            else if (j == high) 
                temp[k] = a[i++];
            else if (a[j]<a[i]) 
                temp[k] = a[j++];
            else 
                temp[k] = a[i++];
        }    
        for (int k = 0; k < N; k++) 
            a[low + k] = temp[k];         
    }
    static long modInverse(int a, int m) 
    { 
        int g = gcd(a, m); 
        if (g != 1) {
        	
        }          
        else 
        { 
        	return  fexp(a, m - 2, m); 
        }
		return g; 
    } 
   
    
}