#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i < (n); i++)
using namespace std;
using ll = long long;

int main(){
    // ios::sync_with_stdio(false);
    double a,b,c,d,e,f; cin>>a>>b>>c>>d>>e>>f;
    cout << std::fixed << std::setprecision(15);

    double r = f - e + (c*c)/4.0/a/a + (d*d)/4.0/b/b ;
    r = sqrtl(r);
    cout << r << endl;
}