#include "stdio.h"
#include "math.h"
using namespace std;

double a, b;

double Abs(double x) {
	if (x < 0)return x*-1;
	return x;
}

int main() {
	scanf("%lf %lf", &a, &b);
	a = sqrt(Abs(a*a - b*b));
	printf("%.10f\n", a);
	return 0;
}