#include<stdio.h>
int main()
{
	double r, d;
	scanf("%lf %lf", &r, &d);
	double min, mid, max;
	min = 0;
	max = d;
	int i;
	for (i = 0; i < 1003; i++)
	{
		mid = (max + min) / 2;
		if (mid * mid + r * r < d * d)
			min = mid;
		else
			max = mid;
	}
	printf("%.20lf\n", (max + min) / 2);
	return 0;
}