# 1051 Texes
# solved by Isfak Ahmed
x = '{:.2f}'.format(float(input()))
salary = float(x)
if salary > 0 and salary <= 2000:
print("Isento")
else :
if salary > 2000 and salary <= 3000:
salaryTax = salary - 2000
tax = salaryTax * (8/100)
elif salary > 3000 and salary <= 4500:
salaryTax = salary - 3000
tax = 80 + salaryTax *(18/100)
elif salary > 4500 :
salaryTax = salary - 4500
tax = 80 + 270 + salaryTax *(28/100)
print("R$ {:.2f}".format(tax))