Add solution confirming correctness but slowness

README.md

@@ -32,7 +32,7 @@ There were 1739 increases in depth when sampling a window
 
 ### Day 2
 
-```sh 
+```sh
 $ ./aoc2021 --two
 The solution for "two" is:
 Horizontal is 1832, depth is 1172, answer is 2147104
@@ -136,12 +136,12 @@ Found 144309 paths through the cave system
 $ ./aoc2021 --thirteen
 The solution for "thirteen" is:
 There are 837 dots after 1 fold
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-###  #  #   #  #    ##   #    #### #  # 
-#    ###   #   # ## # #  #    #  # #  # 
-#    #    #    #  # # #  #  # #  # #  # 
-#### #    ####  ### #  #  ##  #  #  ##  
+#### ###  ####  ##  #  #  ##  #  # #  #
+#    #  #    # #  # # #  #  # #  # #  #
+###  #  #   #  #    ##   #    #### #  #
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+#    #    #    #  # # #  #  # #  # #  #
+#### #    ####  ### #  #  ##  #  #  ##
 This is the activation code
 ```
 
@@ -156,10 +156,11 @@ The result of subtracting the least from most common element quantities is 35727
 
 ### Day fifteen
 
+Today's solution is SLLLLLLOOOOOOOWWW (~75 minutes) but correct!
+
 ```sh
 $ ./aoc2021 --fifteen
 The solution for "fifteen" is:
-fifteen part 1 answer for path
-fifteen part 2 answer for path
+The total risk of the least risky path is 415
+The total risk of the least risky path is 2864
 ```
-