#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
using namespace std;
typedef long long LL;
class LaserShooting
{
public:
double numberOfHits(vector <int> x, vector <int> y1, vector <int> y2)
{
double ans = 0.0;
for(int i=0; i<x.size(); ++i)
{
double a1 = atan2(min(y1[i],y2[i]), x[i]);
double a2 = atan2(max(y1[i],y2[i]), x[i]);
ans += (a2-a1) / M_PI;
}
return ans;
}
};
// BEGIN CUT HERE
#include <ctime>
double start_time;string timer() { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template <typename T> string print_array(const vector<T> &V) { ostringstream os; os << "{ "; for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '\"' << *iter << "\","; os << " }"; return os.str(); }
int verify_case(const double &Expected, const double &Received) { double diff = Expected - Received; if (diff < 0) diff = -diff; if (diff < 1e-9) cerr << "PASSED" << timer() << endl; else { cerr << "FAILED" << timer() << endl; cerr << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } return 0;}
template<int N> struct Case_ { Case_(){start_time=clock();} };
char Test_(...);
int Test_(Case_<0>) {
int x_[] = {1};
vector <int> x(x_, x_+sizeof(x_)/sizeof(*x_));
int y1_[] = {-1};
vector <int> y1(y1_, y1_+sizeof(y1_)/sizeof(*y1_));
int y2_[] = {1};
vector <int> y2(y2_, y2_+sizeof(y2_)/sizeof(*y2_));
double RetVal = 0.5;
return verify_case(RetVal, LaserShooting().numberOfHits(x, y1, y2)); }
int Test_(Case_<1>) {
int x_[] = {1,2};
vector <int> x(x_, x_+sizeof(x_)/sizeof(*x_));
int y1_[] = {-1,-2};
vector <int> y1(y1_, y1_+sizeof(y1_)/sizeof(*y1_));
int y2_[] = {1,2};
vector <int> y2(y2_, y2_+sizeof(y2_)/sizeof(*y2_));
double RetVal = 1.0;
return verify_case(RetVal, LaserShooting().numberOfHits(x, y1, y2)); }
int Test_(Case_<2>) {
int x_[] = {3,4,7,1};
vector <int> x(x_, x_+sizeof(x_)/sizeof(*x_));
int y1_[] = {1,2,3,4};
vector <int> y1(y1_, y1_+sizeof(y1_)/sizeof(*y1_));
int y2_[] = {4,3,2,1};
vector <int> y2(y2_, y2_+sizeof(y2_)/sizeof(*y2_));
double RetVal = 0.4623163952488826;
return verify_case(RetVal, LaserShooting().numberOfHits(x, y1, y2)); }
int Test_(Case_<3>) {
int x_[] = {134,298,151,942};
vector <int> x(x_, x_+sizeof(x_)/sizeof(*x_));
int y1_[] = {-753,-76,19,568};
vector <int> y1(y1_, y1_+sizeof(y1_)/sizeof(*y1_));
int y2_[] = {440,689,-39,672};
vector <int> y2(y2_, y2_+sizeof(y2_)/sizeof(*y2_));
double RetVal = 1.444210260641501;
return verify_case(RetVal, LaserShooting().numberOfHits(x, y1, y2)); }
template<int N> void Run_() { cerr << "Test Case #" << N << "..." << flush; Test_(Case_<N>()); Run_<sizeof(Test_(Case_<N+1>()))==1 ? -1 : N+1>(); }
template<> void Run_<-1>() {}
int main() { Run_<0>(); }
// END CUT HERE