diff --git a/2024/bonus/day05/is_correct/main.tf b/2024/bonus/day05/is_correct/main.tf
new file mode 100644
index 0000000..cde3103
--- /dev/null
+++ b/2024/bonus/day05/is_correct/main.tf
@@ -0,0 +1,21 @@
+variable "update" {
+  type = list(number)
+}
+
+variable "disallow_rules" {
+  type = map(list(number))
+}
+
+locals {
+  not_disallowed = alltrue([
+    for i in range(1, length(var.update)) :
+    !contains(
+      flatten([for j in range(i) : lookup(var.disallow_rules, var.update[j], [])]),
+      var.update[i]
+    )
+  ])
+}
+
+output "valid" {
+  value = local.not_disallowed ? var.update[floor(length(var.update) / 2)] : 0
+}
diff --git a/2024/bonus/day05/main.tf b/2024/bonus/day05/main.tf
new file mode 100644
index 0000000..f553da5
--- /dev/null
+++ b/2024/bonus/day05/main.tf
@@ -0,0 +1,23 @@
+variable "input" {
+  type = string
+}
+
+locals {
+  parts          = split("\n\n", chomp(var.input))
+  rules          = [for rule_line in split("\n", local.parts[0]) : [for v in split("|", rule_line) : tonumber(v)]]
+  disallow_rules = { for rule in local.rules : rule[1] => rule[0]... }
+
+  updates = [for update_line in split("\n", local.parts[1]) : [for v in split(",", update_line) : tonumber(v)]]
+}
+
+module "is_valid" {
+  source = "./is_correct"
+  count  = length(local.updates)
+
+  update         = local.updates[count.index]
+  disallow_rules = local.disallow_rules
+}
+
+output "part1" {
+  value = sum(module.is_valid[*].valid)
+}
diff --git a/2024/bonus/main.tf b/2024/bonus/main.tf
index 45fa707..ba870c4 100644
--- a/2024/bonus/main.tf
+++ b/2024/bonus/main.tf
@@ -56,3 +56,12 @@ output "day03_2" {
 # output "day04_2" {
 #   value = module.day04.part2
 # }
+
+module "day05" {
+  source = "./day05"
+  input  = file("../inputs/05.txt")
+}
+
+output "day05_1" {
+  value = module.day05.part1
+}
diff --git a/2024/bonus/tests.tftest.hcl b/2024/bonus/tests.tftest.hcl
index 4bfe25e..a4669de 100644
--- a/2024/bonus/tests.tftest.hcl
+++ b/2024/bonus/tests.tftest.hcl
@@ -113,3 +113,20 @@ run "day4" {
     error_message = "Part2 output is wrong"
   }
 }
+
+run "day5_1" {
+  command = plan
+
+  module {
+    source = "./day05"
+  }
+
+  variables {
+    input = file("../tests/samples/05.txt")
+  }
+
+  assert {
+    condition     = output.part1 == 143
+    error_message = "Part1 output is wrong"
+  }
+}