File slicing

# Sometimes when programmers get bored or want to have a
# bit of fun, they add a harmless Easter Egg to their program.
# Modify Exercise 7.2,  so that it prints a
#funny message when the user types in the exact file name “na na boo
#boo”.
# The program should behave normally for all other files which
# exist and don’t exist. Here is a sample execution of the program:

# python egg.py
# Enter the file name: mbox.txt
# There were 1797 subject lines in mbox.txt
# python egg.py
# Enter the file name: missing.tyxt
# File cannot be opened: missing.tyxt
# python egg.py
# Enter the file name: na na boo boo
# NA NA BOO BOO TO YOU - You have been punk'd!

fname = input('Enter file name: ')
count = 0
if fname == 'na na boo boo':
    print("NA NA BOO BOO TO YOU - You have been punk'd")
    quit()
try:
    fhand = open(fname)
except:
    print('File cannot be opened: ', fname)
    quit()
for line in fhand:
    line = line.rstrip()
    if line.startswith('X-DSPAM-Confidence:'):
        #print(line)
        pos = line.find(':')
        slice = line[pos+1:]
        fslice = float(slice)
        #print(fslice)
        count = count + 1
print('There were ', count, 'subject lines in', fname)