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