import java.util.*;

class Task3
{
	public static void main (String[] args)
	{
		int m, n;
		double S = 0;
		Scanner in = new Scanner(System.in);
		m = in.nextInt();
		n = in.nextInt();
		for (int i = 1; i <= m; i++)
		{
			for (int j = 1; j <= n; j++)
			{
				S += 1.0/(i + j*j);
			}
		}
		
		System.out.println(S);
	}
}