diff --git a/aoc.cpp b/aoc.cpp
index 77b83cb..b583c8a 100644
--- a/aoc.cpp
+++ b/aoc.cpp
@@ -4,6 +4,9 @@
 #include <expected>
 #include <system_error>
 #include <ranges>
+#include <string>
+#include <algorithm>
+#include <numeric>
 
 #include "fmt/format.h"
 
@@ -11,14 +14,13 @@
 
 namespace vfp {
 using namespace aoc::types;
-using page_order_rule = std::vector<i32>;
-
-class manual_updates {};
+using order_rule = std::vector<i32>;
 }
 
 auto entry([[maybe_unused]]std::span<char const*> const& args) -> std::expected<void, aoc::error> {
     using namespace std::string_view_literals;
-    auto txtres = aoc::read_text("./dat/24/ex/05.txt");
+    // auto txtres = aoc::read_text("./dat/24/ex/05.txt");
+    auto txtres = aoc::read_text("./dat/24/re/05.txt");
     if (!txtres) return std::unexpected(txtres.error());
     auto const txt = *txtres;
 
@@ -26,22 +28,78 @@ auto entry([[maybe_unused]]std::span<char const*> const& args) -> std::expected<
     auto lines = txt | std::views::split("\n"sv)
                      | std::views::transform([](auto const& str) { return std::string_view(str); });
 
-    auto rules   = lines | std::views::take_while(not_empty)
-                         | std::ranges::to<std::vector>();
-    auto updates = lines | std::views::drop_while(not_empty) | std::views::drop(1)
-                         | std::ranges::to<std::vector>();
+    auto rules_str = lines | std::views::take_while(not_empty)
+                           | std::ranges::to<std::vector>();
+    auto updates_str = lines | std::views::drop_while(not_empty)
+                             | std::views::drop(1)
+                             | std::views::take_while(not_empty)
+                             | std::ranges::to<std::vector>();
 
+    // fmt::print("rules:\n");
+    // std::ranges::for_each(rules_str,  [](auto const& str) {
+    //     fmt::print("  \"{}\"\n", str);
+    // });
+    // fmt::print("\n");
+    //
+    // fmt::print("updates:\n");
+    // std::ranges::for_each(updates_str,  [](auto const& str) {
+    //     fmt::print("  \"{}\"\n", str);
+    // });
 
-    fmt::print("rules:\n");
-    std::ranges::for_each(rules,  [](auto const& str) {
-        fmt::print("{}\n", str);
+    auto order_rules = rules_str | std::views::transform([](auto const& str) {
+        return str | std::views::split("|"sv)
+                   | std::views::transform([](auto const& num_str) {
+                         return std::stoi(std::string{std::begin(num_str), std::end(num_str)});
+                   }) | std::ranges::to<std::vector>();
+    }) | std::ranges::to<std::vector>();
+
+    auto updates = updates_str | std::views::transform([](auto const& str) {
+        return str | std::views::split(","sv)
+                   | std::views::transform([](auto const& num_str) {
+                         return std::stoi(std::string{std::begin(num_str), std::end(num_str)});
+                   }) | std::ranges::to<std::vector>();
+    }) | std::ranges::to<std::vector>();
+
+    // std::ranges::for_each(order_rules, [](auto const& rule) {
+    //     std::ranges::for_each(rule, [](auto const& page) {
+    //         fmt::print("{} ", page);
+    //     });
+    //     fmt::print("\n");
+    // });
+    //
+    // std::ranges::for_each(updates, [](auto const& update) {
+    //     std::ranges::for_each(update, [](auto const& page) {
+    //         fmt::print("{}, ", page);
+    //     });
+    //     fmt::print("\n");
+    // });
+
+    auto valid_updates = updates | std::views::filter([&](auto const& pages) {
+        return std::ranges::all_of(order_rules, [&](auto const& rule) {
+            auto const a = std::ranges::find(pages, rule[0]);
+            auto const b = std::ranges::find(pages, rule[1]);
+            return a < b || a == std::end(pages) || b == std::end(pages) || a == b;
+        });
     });
 
-    fmt::print("updates:\n");
-    std::ranges::for_each(updates,  [](auto const& str) {
-        fmt::print("{}\n", str);
+    // std::ranges::for_each(valid_updates, [](auto const& update){
+    //     std::ranges::for_each(update, [](auto const& page) {
+    //         fmt::print("{}, ", page);
+    //     });
+    //     fmt::print("\n");
+    // });
+
+    auto mids = valid_updates | std::views::transform([](auto const& updates) {
+        return *std::ranges::next(std::begin(updates), updates.size() / 2);
     });
 
+    // std::ranges::for_each(mids, [](auto const& mid) {
+    //     fmt::print("{}\n", mid);
+    // });
+
+    auto const sum = std::accumulate(std::begin(mids), std::end(mids), 0);
+    fmt::print("Part A: {}\n", sum);
+
     return {};
 }