using namespace std; int main() { double w,s; cin>>w; if(w<=10){ s=0.2+w*0.8; cout<<fixed<<setprecision(2)<<s; } else if(w<=20){ s=0.2+10*0.8+(w-10)*0.75; cout<<fixed<<setprecision(2)<<s; } else if(w<=30){ s=0.2+10*0.75+10*0.8+(w-20)*0.7; cout<<fixed<<setprecision(2)<<s; } if(w>30){ cout<<"Fail"<<endl; cout<<fixed<<setprecision(2)<<s; } return 0; }