#include<iostream>
using namespace std;
int main ()
{
    float a;
    cin>>a;
    if(a<=2000.00)
    {
        printf("Isento");
    }
    else if(a<=3000.00)
    printf("R$ %.2lf",0.08*(a-2000.00));
    else if(a<=4500.00)
    printf("R$ %.2lf",80+0.18*(a-3000.00));
    else printf("R$ %.2lf",350+0.28*(a-4500.00));
    return 0;
}