#include<stdio.h>
double sqrt(double x)
{
	double min, mid, max;
	int i;
	min = 0;
	max = 1;
	while (max * max <= x)
		max *= 2;
	for (i = 0; i < 100; i++)
	{
		mid = (max + min) / 2;
		if (mid * mid > x)
			max = mid;
		else
			min = mid;
	}
	return min;
}
int main()
{
	int a, b;
	scanf("%d %d", &a, &b);
	if (a < b)
		printf("%.20lf\n", sqrt((double)(b * b - a * a)));
	else if (a > b)
		printf("%.20lf\n", sqrt((double)(a * a - b * b)));
	else
		printf("%.20lf\n", a * sqrt(2.0));
	return 0;
}