#include <bits/stdc++.h>

//const static double	de_PI	= 3.14159265358979323846;
//const static int	de_MOD	= 1000000007;
const static int	de_MAX	= 999999999;
//const static int	de_MIN = -999999999;

int main(void) {

	//std::ifstream inf("123.txt");	std::cin.rdbuf(inf.rdbuf());

	double a = 0, b = 0;
	std::cin >> a >> b;

	double ans1 = std::sqrt(a*a + b*b);
	double ans2 = de_MAX;

	if (a != b) {
		if (a < b) { ans2 = std::sqrt(b*b - a*a); }
		else { ans2 = std::sqrt(a*a - b*b); }
	}

	if (ans1 > ans2) {
		std::cout << std::fixed << std::setprecision(10) << ans2 << std::endl;
	}
	else {
		std::cout << std::fixed << std::setprecision(10) << ans1 << std::endl;
	}

}