URI 1051 solution

#include <iostream>

#include <iomanip>

using namespace std;

int main()

{

    double n;

    cin>>n;

    if(n<=2000.00)

    {

        cout<<"Isento"<<endl;

    }

    else

    {

        double increase,tax;

        if(n>2000.00 &&n<=3000.00)

        {

            increase=n-2000.00;

            tax=increase/100.00*8.00;

        }

        else if(n>3000.00 && n<=4500.00)

        {

            increase=n-3000.00;

            tax=increase/100.00*18.00+80.00;

        }

        else

        {

            increase=n-4500.00;

            tax=increase/100.00*28.00+350.00;

        }

         cout<<"R$ "<<fixed<<setprecision(2)<<tax<<endl;

    }

    return 0;

}