uri 1051

#include <stdio.h>
int main()
{
    float a,t;
    scanf("%f",&a);
    if(a>0.00 && a<2000.00) printf("Isento\n");
    else {
        if(a>2000.01 && a<3000.00){
        a = a-2000.00;
        t = ((8*a)/100);
        printf("R$ %.2f\n",t);
    }
    else if(a>3000.01 && a<4500.00){
        a = a-3000.00;
        t = ((18*a)/100) + ((8*1000.00)/100);
        printf("R$ %.2f\n",t);
    }
    else if(a>4500.00 ){
        a = a-4500.00;
        t = ((28*a)/100) +((18*1500.00)/100) + ((8*1000.00)/100);
        printf("R$ %.2f\n",t);
    }
    }

    return 0;

}