#include<bits/stdc++.h>
using namespace std;

int main(){
	double a,b,c;
	cin >> a >> b;
	if(a==b) printf("%.8lf\n",sqrt(a*a+b*b));
	else{
		c=max(a,b);
		a=min(a,b);
		printf("%.8lf\n",sqrt(c*c-a*a));
	}
	return 0;
}