Fix option count computation

README.md

@@ -2,5 +2,5 @@ How to run:
 
 ```
 docker image build --quiet --tag runall-image .
-docker container run --tty --rm --read-only runall-image
+docker container run --tty --rm --read-only --memory=6m runall-image
 ```

runall.py

@@ -21,7 +21,8 @@ def check_pairs(script, pairs):
 
 def find_script(pairs, max_length):
     candidates = []
-    total_options = len(string.printable) ** max_length
+    chars = len(string.printable)
+    total_options = int((chars ** (max_length + 1) - 1) / (chars - 1))
     current_option = 0
 
     for length in range(max_length + 1):