Interactive EvenOdd in python

CODE SNIPPEST:

print "****************  EVEN ODD CALCULATOR  ****************"
even_list=[]
odd_list=[]
flag=0
ch='y'
while ch=='y':
    print "Current Even_list:\n"+str(even_list)
    print "Current Odd_list:\n"+str(odd_list)
    num = raw_input("Enter a Number to Check:\t")
    if num in even_list:
        print num+" is even. Already in Even List"
    elif num in odd_list:
        print num+" is odd. Already in Odd List"
    else:
        try:
            if int(num) % 2 == 0:
                msg = num+" is an even number... Do you want to enter it in Even List?(y/n)"
                res = raw_input(msg)
                if res=='y':
                    even_list.append(num)
                    print num+" added in Even List"
                    flag=1
                elif res=='n':
                    print "Exiting..."
                else:
                    print "Wrong Input. Exiting..."
            else:
                msg = num+" is an odd number... Do you want to enter it in Odd List?(y/n)"
                res = raw_input(msg)
                if res=='y':
                    odd_list.append(num)
                    print num+" added in Odd List"
                    flag=2
                elif res=='n':
                    print "Exiting..."
                else:
                    print "Wrong Input. Exiting..."
        except:
            print "Please enter a Integer Value"

        if flag==1:
            print "Updated Even_list:\n"+str(even_list)
        elif flag==2:
            print "Updated Odd_list:\n"+str(odd_list)
    ch=raw_input("Do you want to continue(Y/n)?")
    if ch.lower() != 'y' and ch.lower() != 'n':
        ch = raw_input("Please type (Y/n)?")
    if ch.lower() != 'y':
        ch='n'
        print "Exiting..."
        print "-----------------------------------\nEVEN NUMBERS: %s\nODD NUMBERS: %s" %(str(even_list),str(odd_list));

OUTPUT:

root@Avinash:~/python_codes# python evenodd.py
****************  EVEN ODD CALCULATOR  ****************
Current Even_list:
[]
Current Odd_list:
[]
Enter a Number to Check:    2
2 is an even number... Do you want to enter it in Even List?(y/n)y
2 added in Even List
Updated Even_list:
['2']
Do you want to continue(Y/n)?y
Current Even_list:
['2']
Current Odd_list:
[]
Enter a Number to Check:    3
3 is an odd number... Do you want to enter it in Odd List?(y/n)y
3 added in Odd List
Updated Odd_list:
['3']
Do you want to continue(Y/n)?n
Exiting...
-----------------------------------
EVEN NUMBERS: ['2']
ODD NUMBERS: ['3']
root@Avinash:~/python_codes#