diff --git a/days/src/main/kotlin/Day04.kt b/days/src/main/kotlin/Day04.kt
index 2bcbcb9..620a016 100644
--- a/days/src/main/kotlin/Day04.kt
+++ b/days/src/main/kotlin/Day04.kt
@@ -12,17 +12,16 @@ typealias Entries = List<Entry>
 class Day04(@Text val input: Input<String>) {
 
     val entries: List<Entries> = input.value.trim().split("\n\n").map {
-        it.replace("\n", " ")
-            .splitToSequence(" ")
-            .map { it.split(":") }
-            .map { (k, v) -> k.trim() to v.trim() }
-            .toList()
+        it.replace("\n", " ").split(" ").map { it.split(":").let { (k, v) -> k.trim() to v.trim() } }
     }
 
     private fun Entries.hasRequiredKeys() = map { it.first }
         .containsAll(listOf("byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"))
 
-    fun part1(): Int = entries.count { it.hasRequiredKeys() }
+    fun part1() = entries.count { it.hasRequiredKeys() }
+
+    private val hclRegex = "^#[0-9a-f]{6}$".toRegex()
+    private val pidRegex = "^[0-9]{9}$".toRegex()
 
     private fun Entry.hasValidValues() = let { (k, v) ->
         when (k) {
@@ -34,18 +33,14 @@ class Day04(@Text val input: Input<String>) {
                 v.endsWith("in") -> v.removeSuffix("in").toInt() in 59..76
                 else -> false
             }
-            "hcl" -> v.matches("^#[0-9a-f]{6}$".toRegex())
+            "hcl" -> v.matches(hclRegex)
             "ecl" -> v in arrayOf("amb", "blu", "brn", "gry", "grn", "hzl", "oth")
-            "pid" -> v.matches("^[0-9]{9}$".toRegex())
+            "pid" -> v.matches(pidRegex)
             else -> true
         }
     }
 
-    fun part2() = entries
-        .asSequence()
-        .filter { it.hasRequiredKeys() }
-        .filter { it.all { it.hasValidValues() } }
-        .count()
+    fun part2() = entries.count { it.hasRequiredKeys() && it.all { it.hasValidValues() } }
 }
 
 fun main() = with(createDay<Day04>()) {