#
#  A simple federal income tax caluclator that doesn't consider any deductions
#

#
#  Introduce constants to make it easier to update the program when the
#  boundaries for the tax brackets change.
#
TAX_BRACKET_1 = 40726
TAX_BRACKET_2 = 81452
TAX_BRACKET_3 = 126264
RATE_1 = 0.15
RATE_2 = 0.22
RATE_3 = 0.26
RATE_4 = 0.29

income = input("Enter your annual income: ")

if (income < TAX_BRACKET_1):
  tax = income * RATE_1
elif (income < TAX_BRACKET_2):
  tax = TAX_BRACKET_1 * RATE_1 + (income - TAX_BRACKET_1) * RATE_2
elif (income < TAX_BRACKET_3):
  tax = TAX_BRACKET_1 * RATE_1 + (TAX_BRACKET_2 - TAX_BRACKET_1) * RATE_2 + (income - TAX_BRACKET_2) * RATE_3
else:
  tax = TAX_BRACKET_1 * RATE_1 + (TAX_BRACKET_2 - TAX_BRACKET_1) * RATE_2 + (TAX_BRACKET_3 - TAX_BRACKET_2) * RATE_3 + (income - TAX_BRACKET_3) * RATE_4

#
#  Format output to 2 decimal places
#
print "Your tax payable is %.2f" % tax