diff --git a/learn_bpe.py b/learn_bpe.py
index 5e92b2c..034792f 100755
--- a/learn_bpe.py
+++ b/learn_bpe.py
@@ -43,6 +43,7 @@ def create_parser():
         '--input', '-i', type=argparse.FileType('r'), default=sys.stdin,
         metavar='PATH',
         help="Input text (default: standard input).")
+
     parser.add_argument(
         '--output', '-o', type=argparse.FileType('w'), default=sys.stdout,
         metavar='PATH',
@@ -53,11 +54,12 @@ def create_parser():
     parser.add_argument(
         '--min-frequency', type=int, default=2, metavar='FREQ',
         help='Stop if no symbol pair has frequency >= FREQ (default: %(default)s))')
+    parser.add_argument('--dict-input', action="store_true",
+        help="If set, input file is interpreted as a dictionary where each line contains a word-count pair")
     parser.add_argument(
         '--verbose', '-v', action="store_true",
         help="verbose mode.")
-    parser.add_argument('--is_dict', '-is_dict', type=bool, default=False,
-        help="Specify this argument if the input file is a dictionary where each line contains a word count pair")
+
     return parser
 
 def get_vocabulary(fobj, is_dict=False):
@@ -66,8 +68,8 @@ def get_vocabulary(fobj, is_dict=False):
     vocab = Counter()
     for line in fobj:
         if is_dict:
-            word_count = line.strip().split()
-            vocab[word_count[0]] = int(word_count[1])
+            word, count = line.strip().split()
+            vocab[word] = int(count)
         else:
             for word in line.split():
                 vocab[word] += 1
@@ -194,7 +196,7 @@ if __name__ == '__main__':
     if args.output.name != '<stdout>':
         args.output = codecs.open(args.output.name, 'w', encoding='utf-8')
 
-    vocab = get_vocabulary(args.input, is_dict = args.is_dict)
+    vocab = get_vocabulary(args.input, is_dict = args.dict_input)
     vocab = dict([(tuple(x)+('</w>',) ,y) for (x,y) in vocab.items()])
     sorted_vocab = sorted(vocab.items(), key=lambda x: x[1], reverse=True)