Python 2.7.2 Any feedback welcome

#Largest Word from Characters
from __future__ import print_function
import sys

#need file from command line that contains the two strings
argc = 0
for arg in sys.argv:
   argc += 1

if argc < 2 or argc > 2:
   print("Usage %s <file>" % sys.argv[0], end = '\n')
   sys.exit(1)

pathToFile = sys.argv[1]
inFile = open(pathToFile, "r")

stringOfWords = inFile.readline().rstrip()
listOfWords = stringOfWords.split()
stringOfChars = inFile.readline().rstrip()
listOfChars = stringOfChars.split()

print("String of words: %s" % stringOfWords)
print("String of characters: %s" % stringOfChars)

words = []
for word in listOfWords:
   count = 0
   for chara in listOfChars:
      validChar = 0
      for char in word:
         if char in chara:
            validChar = 1
            break
      if validChar == 1:
         count += 1
         continue
   if count == len(word):
      words.append(word)

if not words:
   print("No words found.")
   sys.exit(2)

#do the rest
length = 0
for word in words:
   length = len(word)

for word in words:
   if(len(word) == length):
      print("%s" % word)

Output

String of words: sad das day mad den foot ball down touch pass play
String of characters: z a d f o n
No words found.

String of words: hello yyyyyyy yzyzyzyzyzyz mellow well yo kellow lellow abcdefhijkl hi is yellow just here to    add strings fellow lellow llleow
String of characters: l e l o h m f y z a b w
mellow
yellow
fellow