问如何正确配置python 3的使用以避免NameError:未定义名称“”

EN

def file_name(fname):
    try:
        fhand = open(fname)
    except:
        print('File cannot be opened: ', fname)
        quit()
    count = 0
    starts_with = **input**('Entries starts with: ')
    for line in fhand:
        if line.startswith(starts_with):
            count = count + 1
print('There were ', count, ' subject lines in', fname)

Hou-Pengs-MBP:PY4E houpengzhu$ python File.py
Enter the file name: hw.py
Entries starts with: print 
('There were ', 1, ' subject lines in', 'hw.py')

Hou-Pengs-MBP:PY4E houpengzhu$ python File.py
Enter the file name: hw.py
Traceback (most recent call last):
  File "File.py", line 15, in <module>
    fname = input('Enter the file name: ')
  File "<string>", line 1, in <module>
NameError: name 'hw' is not defined