#include <iostream>

using namespace std;

int main() {
    double a, b, f;
    cout<<"Ââåäèòå äëèíó ñòåíû:";
    cin>>a;
    cout<<"Ââåäèòå âûñîòó ñòåíû:";
    cin>>b;
    cout<<"Ðóëîí îáîåâ ðàçìåðîâ: 12*1"<< endl;
    cout<<"Ââåäèòå öåíó ðóëîíà:";
    cin>>f;
    cout<<(a*b)/(12*1)*f<< endl;
    

    system ("pause");
    return 0;
}