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

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    using ld = long double;
    ld a,b,c,d,e,f; cin >> a >> b >> c >> d >> e >> f;
    c /= a, d /= a, e /= a, f /= a;
    // (x+c/2)^2 + (y+d/2)^2 -c^2/4 -d^2/4 + e = f
    ld r2 = f - e + c * c / 4.0 + d * d / 4.0;
    cout << fixed << setprecision(20) << sqrtl(r2) << endl;
}