#include<bits/stdc++.h>
#include <atcoder/all>
#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace atcoder;
using mint=modint998244353;
using namespace std;
using ll=long long;
using ul=unsigned long long;
int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
int dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};
using Graph=vector<vector<int>>;
ll op(ll a,ll b){return min(a,b);}
ll e(){return 2e9;}
int main(){
    double a,b,c,d,e,f;
    cin>>a>>b>>c>>d>>e>>f;
    c/=a,d/=a,e/=a,f/=a;
    cout<<fixed<<setprecision(5)<<sqrt((c*c+d*d)/4.0+f-e)<<endl;
}