#include<bits/stdc++.h>
#define int long long
using namespace std;
signed main(){
    int a,b,c,d,e,f;
    cin>>a>>b>>c>>d>>e>>f;
    f-=e;
    c/=a,d/=a,e/=a,f/=a;
    cout<<fixed<<setprecision(16)<<sqrt(f+c*c/4+d*d/4)<<endl;
}