diff --git a/day_7/code b/day_7/code
index 0dbb9f9..9476f10 100644
Binary files a/day_7/code and b/day_7/code differ
diff --git a/day_7/code.hi b/day_7/code.hi
index bcc6ae0..6028f0e 100644
Binary files a/day_7/code.hi and b/day_7/code.hi differ
diff --git a/day_7/code.hs b/day_7/code.hs
index 70e0db5..b163651 100644
--- a/day_7/code.hs
+++ b/day_7/code.hs
@@ -26,6 +26,8 @@ minimumsSnd [] = []
 minimumsSnd xs = filter ((==) minsnd . snd) xs
     where minsnd = minimum (map snd xs)
 
+sumK n = ((n+1)*n) `div` 2
+
 main :: IO ()
 main = do
     input <- getContents
@@ -35,11 +37,11 @@ main = do
         splitStr "," input
     }
     let cases = do {
-        map (\x -> (x, sum (map (\y -> do {
-            sum [1..((abs (y-x)))]
-        }) crabs))) [(minimum crabs)..(maximum crabs)]
+        map 
+        (\x -> (x, sum (map (\y -> sumK (abs (y-x))) crabs)))
+        [(minimum crabs)..(maximum crabs)]
     }
     let min = minimumsSnd
     putStrLn $ show $ snd $ head $ min cases -- ans to part 2
 
--- C'est un code pas du tout efficace
\ No newline at end of file
+-- Gross, but it works
\ No newline at end of file
diff --git a/day_7/code.o b/day_7/code.o
index baa859e..756f16b 100644
Binary files a/day_7/code.o and b/day_7/code.o differ