#include <iostream>
#include <math.h>
#include <iomanip>
using namespace std;

int main(){
	int a,b;
	cin >> a >> b;
	double ans = 0;
	
	/*
		a^2 + b^2 = c^2 -> sqrt(a^2+b^2)
		a^2 + c^2 = b^2 -> sqrt(b^2-a^2)
		b^2 + c^2 = a^2 -> sqrt(a^2-b^2)
	*/
	//ans = sqrt(a*a+b*b);

	if(b*b-a*a > 0){//b^2-a^2=0の時は？→考慮しないと0が出力
		ans = (double)sqrt(b*b-a*a);
	}else if(a*a-b*b > 0){
		ans = (double)sqrt(a*a-b*b);
	}else{
		ans = (double)sqrt(a*a+b*b);
	}
	
	cout << fixed << setprecision(7) << ans  << endl;
	return 0;
}