#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using vin=vector<int>;
using vll=vector<long long>;
using vvin=vector<vector<int>>;
using vvll=vector<vector<long long>>;
using vstr=vector<string>;
using vvstr=vector<vector<string>>;
using vch=vector<char>;
using vvch=vector<vector<char>>;
using vbo=vector<bool>;
using vvbo=vector<vector<bool>>;
using vpii=vector<pair<int,int>>;
using pqsin=priority_queue<int,vector<int>,greater<int>>;
#define mp make_pair
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,s,n) for(int i=(s);i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define decp(n) cout<<fixed<<setprecision((int)n)
const ll inf=1e9+7;
const ll INF=1e18;

int main(){
    decp(10);
    double a,b,c,d,e,f;cin>>a>>b>>c>>d>>e>>f;
    double x=-c/(2.0*a),y=-d/(2.0*b);
    double tmp=f-a*x*x-b*y*y-c*x-d*y-e;
    cout<<sqrt(tmp)<<endl;
    //cout<<sqrt(4.0*a*(f-e)+c*c+d*d)/(2.0*abs(a))<<endl;
    //cout<<sqrt((f-e)/a+c*c/(4.0*a*a)+d*d/(4.0*b*b))<<endl;
}