Coin change exercise program

import random

print('The purpose of this game is to enter a number of coins value that')
print('adds up to a display target value')
print('Enter coin values as 1-penny, 5-nickel, 10-dime, and 25-quarter')
print('Hit return after the last entered coin value')
print('----------------')

terminate = False
empty_str = ''

#To give targeted value
while not terminate:
    amount = random.randint(1,99)
    print('Enter coins value that add ups to {}'.format(amount))
    game_over = False
    total = 0

    while not game_over:
        valid_entry = False

        while not valid_entry:
            if total == 0:
                entry = input('Enter first coins: ')
            else:
                entry = input('Enter next coins: ')


            if entry in {empty_str, '1', '5','10','25'}:
                valid_entry = True
            else:
                print('Invalid entry')

        if entry == empty_str:
            if total == amount:
                print('Correct!')
            else:
                print('Sorry you only entered {} cents'.format(total))
            game_over = True

        else:
            total = total + int(entry)
            if total > amount:
                print('Sorry total amount exceed {} cents.'.format(amount))
                game_over = True

            if game_over:
                entry = input('Try again ?(Y/N)' )

                if entry == 'N':
                    terminate = True

print('Thanks for playing. Goodbye!')