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.util.Arrays;
import java.util.Map.Entry;
import java.util.StringTokenizer;
import java.util.TreeMap;


public class Main {
	static Scanner sc = new Scanner(System.in);
	
	/*public static void main(String[] args) throws IOException{
		int n=sc.nextInt();
		int x=sc.nextInt();
		int y=sc.nextInt();
		
		int[] a= new int[n];
		
		for (int i = 0; i < a.length; i++) {
			a[i]=sc.nextInt();
		}
		for (int i = 0; i < a.length; i++) {
			boolean f1=true;
			int f=i-x;
			if(f<0)
			{
				f=0;
			}
			for (int j = f; j < i; j++) {
				if(a[j]<a[i])
				{
					f1=false;break;
				}
			}
			boolean f2=true;
			int l=i+y;
			if(l>a.length-1)
			{
				l=a.length-1;
			}
			for (int j = i+1; j <= l; j++) {
				if(a[j]<a[i])
				{
					f1=false;break;
				}
			}
			if(f1 && f2)
			{
				System.out.println(i+1);break;
			}
		}
	}*/
	
	public static void main(String[] args) throws IOException{
		double H=sc.nextDouble();
		double L=sc.nextDouble();
		
		double res=(L*L-H*H)/(2*H);
		
		System.out.println(res);
		
	}
	
	/*public static void main(String[] args) throws IOException{
		int n=sc.nextInt();
		int I=sc.nextInt();
		
		Integer[] a = new Integer[n];
		TreeMap<Integer, Integer> occ= new TreeMap<Integer, Integer>();
		
		for (int i = 0; i < a.length; i++) {
			a[i]=sc.nextInt();
			if(!occ.containsKey(a[i]))
			{
				occ.put(a[i], 1);
			}
			else
			{
				occ.put(a[i], occ.get(a[i]) + 1);

			}
		}
		
		Arrays.sort(a);
		
		int distinct=1;
		
		for (int i = 0; i < a.length-1; i++) {
			if(a[i]!=a[i+1])
			{
				distinct++;
			}
		}
		//System.out.println("distinct: " + distinct);
		
		int bitsOnDisk=I*8;
		
		TreeMap<Integer, Integer> powerTwo= new TreeMap<Integer, Integer>(); 
		
		for (int j = 0; j < 25; j++) {
			powerTwo.put((int)Math.pow(2,j), j);
		}
		
		int bitsTot=0;
		int keep=0;
		for(Entry e: powerTwo.entrySet())
		{
			if((int)e.getValue()*n<=bitsOnDisk)
			{
				keep=(int) e.getKey();
				bitsTot=(int)e.getValue()*n;
			}
		}
		int remove=distinct-keep;
		//System.out.println("Keep: " + keep);
		//System.out.println("Remove: " + remove);
		//System.out.println("bitstot: " + bitsTot);
		int output=0;
		Integer[] o= new Integer[occ.size()]; 
		for(int i=0; i<o.length; i++)
		{
			o[i]=(int) occ.pollFirstEntry().getValue();
		}
		int f=0;
		int l=keep-1;
		int sum=0;
		
		for (int j = 0; j < l; j++) {
			sum+=o[j];
		}
		
		int end=l;
		int max=sum;
		
		sum-=a[f];
		f++;
		l++;
		while(l<o.length)
		{
			sum+=o[l];
			if(sum>max)
			{
				max=sum;
				end=l;
			}
			sum-=a[f];
			f++;
			l++;
		}
		int beg=end-keep+1;
		for (int j = 0; j < beg; j++) {
			output+=o[j];
		}
		for (int j = end+1; j < o.length; j++) {
			output+=o[j];
		}
		
		System.out.println(output);
	}
	*/
	static class Scanner {
		StringTokenizer st;
		BufferedReader br;
 
		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}
 
		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}
 
		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}
 
		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}
 
		public String nextLine() throws IOException {
			return br.readLine();
		}
 
		public double nextDouble() throws IOException {
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			int start = 0;
			boolean dec = false, neg = false;
			if (x.charAt(0) == '-') {
				neg = true;
				start++;
			}
			for (int i = start; i < x.length(); i++)
				if (x.charAt(i) == '.') {
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				} else {
					sb.append(x.charAt(i));
					if (dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg ? -1 : 1);
		}
 
		public boolean ready() throws IOException {
			return br.ready();
		}
 
	}
}