#include<cstdio>

int main(){
    double a;
    scanf("%lf",&a);
    if(a<=2000) printf("Isento");
    else{
        if(a>2000.01&&a<=3000) printf("R$ %.2f",(a-2000)*0.08);
        if(a>3000.01&&a<=4500) printf("R$ %.2f",1000*0.08+(a-3000)*0.18);
        if(a>4500) printf("R$ %.2f",1000*0.08+1500*0.18+(a-4500)*0.28);
    }
    return 0;
}