diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1377554
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.swp

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1377554
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.swp
diff --git a/odds.py b/odds.py
new file mode 100755
index 0000000..6546045
--- /dev/null
+++ b/odds.py
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+#!/usr/bin/python
+
+import sys
+import random
+
+debug = False
+
+def fact(n):
+  if n == 0: return 1
+  return n * fact(n - 1)
+
+success_odds_by_dice = {}
+
+def get_odds(num_dice, indent = 0):
+  global debug, success_odds_by_dice
+  def iprint(val, *args):
+    if debug:
+      print (indent * " ") + str(val).format(*args)
+
+  if num_dice == 0: return 1
+
+  iprint("-- get_odds({}) --", num_dice)
+
+  if num_dice in success_odds_by_dice:
+    iprint("-- odds: {} --", success_odds_by_dice[num_dice])
+    return success_odds_by_dice[num_dice]
+
+  total_odds_success = 0
+
+  num_rolls = pow(6, num_dice)
+  iprint("num rolls with {} dice: {:,}", num_dice, num_rolls)
+  for i in xrange(1, num_dice + 1):
+    remaining_dice = num_dice - i
+    num_rolls_with_i_sixes = pow(5, remaining_dice) * fact(num_dice) / (fact(remaining_dice) * fact(i))
+    for j in xrange(i + 1, num_dice + 1):
+      num_rolls_with_i_sixes 
+    iprint(" num rolls of {} dice with {} six(es): {:,}", num_dice, i, num_rolls_with_i_sixes)
+    odds_i_sixes = num_rolls_with_i_sixes / float(num_rolls)
+    iprint("  odds of that happening: {}", odds_i_sixes)
+    total_odds_success += get_odds(num_dice - i, indent + 3) * odds_i_sixes
+
+  success_odds_by_dice[num_dice] = total_odds_success
+
+  iprint("-- odds: {} --", total_odds_success)
+  return total_odds_success
+
+def get_monte_carlo_odds(iterations, num_dice):
+  global debug
+  successes = 0
+  for i in xrange(0, iterations):
+    dice_left = num_dice
+    while dice_left > 0:
+      num_sixes = 0
+      for j in xrange(0, dice_left):
+        if random.randint(1, 6) == 6:
+          num_sixes += 1
+      if num_sixes == 0:
+        dice_left = 0
+      else:
+        dice_left -= num_sixes
+        if dice_left == 0:
+          successes += 1
+  if debug:
+    print "-- monte carlo: {:,} / {:,} --".format(successes, iterations)
+  return successes / float(iterations)
+
+def find_flag(flag):
+  if flag in sys.argv:
+    sys.argv.remove(flag)
+    return True
+  return False
+
+debug = find_flag("debug")
+simple_output = find_flag("simple")
+do_monte_carlo = not simple_output and not find_flag("no_mc")
+
+dice = int(sys.argv[1])
+odds = get_odds(dice)
+monte_carlo_iters = 100000
+if len(sys.argv) > 2:
+  monte_carlo_iters = int(sys.argv[2])
+
+if do_monte_carlo:
+  monte_carlo_odds = get_monte_carlo_odds(monte_carlo_iters, dice)
+
+if debug:
+  # extra line to separate debug output
+  print
+if simple_output:
+  print odds
+else:
+  odds_str = "odds of getting donuts with {} dice: {:.2}%".format(dice, odds * 100)
+  if do_monte_carlo:
+    odds_str += ", monte carlo with {:,} iterations gives: {:.2}%".format(monte_carlo_iters, monte_carlo_odds * 100)
+  print odds_str