Calculate age in Python

Calculate age:
Takes input a) Future Date(optional) b)Birth Date
Validates for leap year and some basic input validations

 vi age.py
#########START OF SCRIPT#########
from sys import argv
from datetime import datetime,timedelta

oddmonths = [ '01','05','07','08','10','12' ]

def getdata():
     global clockyear
     global clockmonth
     global clockday
     global iyear
     global imonth
     global iday
     global ageyear
     global agemonth
     global ageday
     ask = raw_input("\nDo you want to calc age at a certain date?...Press Y|y|yes:\t")
     if ask == "":
        print "Invalid Response...Exiting"
        exit(1)
     elif ask in ['Y', 'y', 'yes'] :
       get = raw_input("\nPlease enter the from date as yyyy/mm/dd:\t")
       if len(get)< 10:
         print "Invalid Date...Exiting"
       else:
         clock = get.split("/")
         clockyear = int(clock[0])
         clockmonth = int(clock[1])
         clockday = int(clock[2])
     else:
         clock = datetime.now()
         clockyear = clock.year
         clockmonth = clock.month
         clockday = clock.day
    #Assign input variables
     getdetail = raw_input("\nEnter you date of birth as yyyy/mm/dd:\t")
     input = getdetail.split("/")
     iyear = int(input[0])
     imonth = int(input[1])
     iday = int(input[2])
     if iyear > clockyear:
        print "\nCal year cannot be > the birth year..Please Enter valid year\n"
        exit(1)
     #Assign age variables
     ageyear = clockyear - iyear
     agemonth = clockmonth - imonth
     ageday = clockday - iday

getdata()


#Assign age variables
#ageyear = clockyear - iyear
#agemonth = clockmonth - imonth
#ageday = clockday - iday

#print "Your ageyear\t:",ageyear
#print "Your age month\t:",agemonth
#print "Your ageday\t:",ageday

##### Function checks for Leap Year
def leapyear(a):
    if a % 400 == 0:
        return True
    elif a % 100 == 0:
        return False
    elif a % 4 == 0:
        return True
    else:
        return False

#Calc month & year
def month(a,b):
  if imonth < 0 or imonth > 12:
     print "You Entered invalid month...Exiting."
     exit(1)
  elif a < imonth:
      return(12+(a-imonth),b-1)
  elif a > imonth:
        return((a-imonth),b)
  else:
        return(0,b)


def prints(ageyear,agemonth,ageday):
        print "\nYour age is:\t%s Years:\t%s Months:\t%s Days\n" % (ageyear,agemonth,ageday)

def age():
        global imonth
        global iyear
        global iday
        global ageyear
        global agemonth
        global ageday
        global clockmonth
        global clockday
        if iday < 0 or iday > 31:
           print "You Entered invalid day...Exiting."
           exit(1)
        elif clockmonth !=03 and ageday >= 0 and agemonth >  0:
             prints(ageyear,agemonth,ageday)
        elif clockmonth !=03 and ageday >= 0 and agemonth < 0:
             agemonth,ageyear = month(clockmonth,ageyear)
             prints(ageyear,agemonth,ageday)
        elif clockmonth !=03 and ageday < 0 and (clockmonth-1) in oddmonths:
             ageday = 31 + ageday
             agemonth,ageyear = month((clockmonth-1),ageyear)
             prints(ageyear,agemonth,ageday)
        elif clockmonth !=03 and ageday < 0 and (clockmonth-1) not in oddmonths:
             ageday = 30 + ageday
             agemonth,ageyear = month((clockmonth-1),ageyear)
             prints(ageyear,agemonth,ageday)
####Condition for Leap Year check
        elif clockmonth == 03 and leapyear(clockyear):
           if ageday >=0:
             agemonth,ageyear = month((clockmonth),ageyear)
             prints(ageyear,agemonth,ageday)
           elif ageday <0:
             ageday = 29 + ageday
             agemonth,ageyear = month((clockmonth-1),ageyear)
             prints(ageyear,agemonth,ageday)
        elif clockmonth == 03 and not leapyear(clockyear):
           print " I am in 03"
           if ageday >=0:
                    agemonth,ageyear = month((clockmonth),ageyear)
                    prints(ageyear,agemonth,ageday)
           elif ageday <0:
                     ageday = 28 + ageday
                     agemonth,ageyear = month((clockmonth-1),ageyear)
                     prints(ageyear,agemonth,ageday)


def main():
        global imonth
        global iyear
        global iday
        if imonth == 02 and leapyear(iyear) and iday >29:
                print "You cannot have >29 days in Feb of a leapyear:\n"
                print "Enter valid day:\n"
        elif imonth == 02 and not leapyear(iyear) and iday >28:
                print "You cannot have >28 days in Feb,if the year is not a leapyear:\n"
                print "Enter valid day:\n"
        else:
                age()

main()

#########END OF SCRIPT#########


Output-1:
############
shaiks@MAC$py age.py

Do you want to calc age at a certain date?...Press Y|y|yes:    y

Please enter the from date as yyyy/mm/dd:    2017/08/31

Enter you date of birth as yyyy/mm/dd:    2000/02/29

Your age is:    17 Years:    6 Months:    2 Days


Output-2:
############
shaiks@MAC$py age.py

Do you want to calc age at a certain date?...Press Y|y|yes:    n

Enter you date of birth as yyyy/mm/dd:    2000/02/29

Your age is:    15 Years:    7 Months:    27 Days


Error Handling:
###############
shaiks@MAC$py age.py


Do you want to calc age at a certain date?...Press Y|y|yes:    y

Please enter the from date as yyyy/mm/dd:    2017/08/31

Enter you date of birth as yyyy/mm/dd:    2000/02/31
You cannot have >29 days in Feb of a leapyear:

Enter valid day: