#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)n; ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>istream&operator >>(istream&is,vector<T>&vec){for(T&x:vec)is>>x;return is;}
template<class T>inline void out(T t){cout << t << "\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout << t << " ";out(ts...);}
template<class T>inline bool CHMIN(T&a,T b){if(a > b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a < b){a = b;return true;}return false;}
constexpr int INF = 1e18;



signed main(){
	double A, B, C, D, E, F;
	cin >> A >> B >> C >> D >> E >> F;
	if(A != 1) {
		B /= A;
		C /= A;
		D /= A;
		E /= A;
		F /= A;
		A /= A;
	}
	if(B != 1) {
		A /= B;
		C /= B;
		D /= B;
		E /= B;
		F /= B;
		B /= B;
	}
	double ans = (double)F - E + (C * C + D * D) / 4;
	ans = sqrt(ans);
	cout << setprecision(20) << ans << endl;
}