#include <iostream>
using namespace std;
int main()
{
// avem suma unei progresii aritmetice 1+3+5+7+9+11
cout << "a. castig saptamanal: " << 3*(1+11)*0.15 << " lei " << endl;
// punctul b
int n;
cout << "n=" ; cin >> n;
cout << "b. castig dupa n zile: " ;
double s=(1+1+(n-1)*2)*n/2, castig=s*0.15;
cout << castig << "\n";
// punctul c
int m;
cout << "m="; cin >> m;
s=(1+1+(m-1)*2)*m/2;
s-=m;
castig=s*0.15;
cout << "c. castigul pe m zile: " << castig;
return 0;
}