problem with for loop using integers

[python_germ]

Ok, so totally green but super keen!

I programmed a 'dice' attack value game, that prompts a user to choose n die to roll and with what 'attack value' the dice will have. the object is for a war board game, not important... Program seems to run fine, but sometimes it runs the 'for' loop more times than the user prompted for.... What am I doing wrong with this for loop? (code below)

while True:
    print("welcome to the dice game!")
    import random
    a=input("how many die would you like to roll? ")
    b=input("what is the attack value of the die? ")
    aa=int(a)
    bb=int(b)
    print('OK... anything ',b,'or less, is a hit!')
    print('Here we go!')
    hit=0
    miss=0
    for x in iter(aa):
        j=random.randint(1,6)
        if j<=bb:
            print(j,'hit')
            j=hit
            hit=hit+1
        if j>bb:
            print(j,'miss')
            j=miss
            miss=miss+1
    print('total hits: ',hit)
    print('total misses: ',miss)
    y=input('would you like to play again (y/n)')
    if y=='y':
        continue
    if y=='n':
        break
    if y!='y' and y!='n':
        print('invalid answer')
        break
print('thanks for playing!')

also not sure how to paste code to include indentation on this forum... sorry.