Finding occurence of sub-string in a string

def count_substring(string, sub_string):
    counter = 0
    for i in range(len(string)):
        if string[i:i + len(sub_string)] == sub_string:
            counter += 1
    return counter


if __name__ == '__main__':
    string = input().strip() #strip() is used to remove all leading and trailing spaces from a string
    sub_string = input().strip()

    count = count_substring(string, sub_string)
    print(count)