#include <iostream>
using namespace std;
int main() {
double sal, tax;
cin >> sal;
if (sal <= 2000) {
printf("Isento\n");
} else {
if (sal >= 2000.01 && sal <= 3000) tax = (sal - 2000) * 0.08;
else if (sal >= 3000.01 && sal <= 4500) tax = (sal - 3000) * 0.18 + 80;
else if (sal >= 4500) tax = (sal - 4500) * 0.28 + 350;
printf("R$ %.2lf\n", tax);
}
return 0;
}