Counting letters and numbers

array = []

counter = 0
number = 0
letter = 0



string = input('Enter: ')

length = len(string)


x = list (string)

array.append(x)


for i in range (length):
    if (array[counter]) is chr:
        letter = letter +1
        counter = counter +1
    if (array[counter]) is int:
        number = number +1
        counter = counter +1
    elif (array[counter]) is ' ':
        counter = counter +1

print (letter)
print (number)