#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	double a, b, c, d, e, f; cin>>a>>b>>c>>d>>e>>f;
	c/=a, d/=a, e/=a, f/=a;
	double r=f-e+c*c/4+d*d/4;
	r=sqrt(r);
	printf("%.7lf\n", r);
	return 0;
}