diff --git a/4/solution.nix b/4/solution.nix
index d354647..661884c 100644
--- a/4/solution.nix
+++ b/4/solution.nix
@@ -3,12 +3,13 @@ with import ../util.nix;
 let
   # read input
   input = readFile ./input;
-  pairs = let 
-    readRange = s: splitPair (a: b: [ (toInt a) (toInt b) ]) (splitString "-" s);
-    readPair = a: b: [ (readRange a) (readRange b) ];
-  in map
-    (line: splitPair readPair (splitString "," line))
-    (splitString "\n" input);
+  pairs =
+    let
+      readRange = s: splitPair (a: b: [ (toInt a) (toInt b) ]) (splitString "-" s);
+      readPair = a: b: [ (readRange a) (readRange b) ];
+    in map
+      (line: splitPair readPair (splitString "," line))
+      (splitString "\n" input);
 
   # overlap functions
   partialOverlap = a1: a2: b1: b2:
@@ -18,7 +19,7 @@ let
 
   # calc overlaps
   hasOverlap = overlapFunc: a: b:
-    splitPair (splitPair overlapFunc a) b  || splitPair (splitPair overlapFunc b) a;
+    splitPair (splitPair overlapFunc a) b || splitPair (splitPair overlapFunc b) a;
   overlaps = overlapFunc: map boolToInt (map (splitPair (hasOverlap overlapFunc)) pairs);
 in {
   part1 = sum (overlaps completeOverlap);