税

#include<stdio.h>
int main(){
    double inc,tax;
    scanf("%lf",&inc);
    if(inc<=2000.00)printf("Isento");
    else if(inc<=3000.00){
        tax=(inc-2000.00)*0.08;
        printf("R$ %.2lf",tax);
    }
    else if(inc<=4500.00){
        tax=80+(inc-3000.00)*0.18;
        printf("R$ %.2lf",tax);
    }
    else{
        tax=350+(inc-4500.00)*0.28;
        printf("R$ %.2lf",tax);
    }
    return 0;
}