Str problem, not counting

[Hann]

Hello! I need some help, I really can't understand something.
I try to count how many times 'a', 'b' or 'c' is introduced in 10 repetitions, using an i contor and range function for this.
When I debug the py file, says:

Error:
File "<input>", line 1, in <module>
NameError: name 'a' is not defined 

The problem is that 'the program' doesn't step over the input function, so the counting for a, b and c doesn't apply.
Here is the code:

count_a = 0
count_b = 0
count_c = 0
char = ['a', 'b', 'c']
choice = '-'
for i in range(1, 11):
    print('Please choose a char from a to c')
    str(input(choice))
    if choice in char:
        print('You have chosen {}'.format(choice))
        count_a += 1
    elif choice in char:
        print(('You have chosen {}'.format(choice)))
        count_b += 1
    elif choice in char:
        print(('You have chosen {}'.format(choice)))
        count_c += 1
    # else:
    #     print('You have chosen an unavailable char, please try again')
print(count_a)
print(count_b)
print(count_c)

Please don't be rough to me...