// Compute Molecules from Mass

#include <iostream>
#include <string>
using namespace std;

int main() {
    
    cout << "Enter mass of hydrocarbon (in grams)\n"
         << "followed by the number of carbon atoms\n"
         << "followed by the number of hydrogen atoms\n"
         << "(e.g. 10.5 2 6): " ;
    
    double Mass;
    int CarbonAtoms;
    int HydrogenAtoms;
    
    cin >> Mass >> CarbonAtoms >> HydrogenAtoms;
    
    const int CarbonAMU = 12;
    const int HydrogenAMU = 1;
    long int FormulaWght = (CarbonAtoms * CarbonAMU) + (HydrogenAtoms * HydrogenAMU);
    const double AvogadroNbr = 6.02e23;
    double Molecules = (Mass / FormulaWght) * AvogadroNbr;
    
    cout << Mass << " grams of a hydrocarbon\nwith "
         << CarbonAtoms << " carbon atom(s) and "
         << HydrogenAtoms << " hydrogen atom(s)\ncontains "
         << Molecules << " molecules" << endl;
    return 0;
}