#include <cstdio>
#include <iostream>
using namespace std;
int main(){
double x,s;
cin >> x;
if(x<= 2000){
cout<< "Isento" ;
}
else{ if(x>2000 && x<=3000.00) s = (x-2000.00) *0.08;
if(x>3000.00 && x<=4500.00 ) s=80+(x-3000.00)*0.18;
if(x>4500.00) s=350 + (x-4500.00)*0.28;
printf("R$ %.2lf",s);
}
return 0;
}