diff --git a/2025/CMakeLists.txt b/2025/CMakeLists.txt
index 7626e6e..348a859 100644
--- a/2025/CMakeLists.txt
+++ b/2025/CMakeLists.txt
@@ -32,4 +32,5 @@ add_day_executables(
     "day02.cpp"
     "day03.cpp"
     "day04.cpp"
+    "day05.cpp"
 )
diff --git a/2025/day05.cpp b/2025/day05.cpp
new file mode 100644
index 0000000..c0d54ab
--- /dev/null
+++ b/2025/day05.cpp
@@ -0,0 +1,90 @@
+#include <span>
+#include <algorithm>
+#include <ranges>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "fmt/std.h"
+
+#include "aoc/types.hpp"
+#include "aoc/utils.hpp"
+
+using namespace std::string_view_literals;
+using namespace aoc::types;
+
+// starts at 50
+[[maybe_unused]]constexpr auto raw_str = R"(
+3-5
+10-14
+16-20
+12-18
+
+1
+5
+8
+11
+17
+32
+)";
+
+static auto entry([[maybe_unused]]std::span<char const*> const& args) -> void {
+    // std::string str{raw_str};
+    auto str = aoc::read_text("./input.txt").value_or("");
+    str = aoc::trim(str);
+
+    fmt::print("INPUT\n");
+    fmt::print("⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼⎽⎼⎻⎺⎻⎼\n");
+    fmt::print("{}\n", str);
+    fmt::print("{}\n", std::string(80, '-'));
+
+    auto id_spec = str | std::views::split("\r\n\r\n"sv) | std::views::transform([](auto const& str) {
+        return aoc::trim({std::begin(str), std::end(str)});
+    }) | std::ranges::to<std::vector>();
+
+    if (id_spec.size() < 2) throw std::runtime_error("ID specification is not valid");
+
+    auto id_range = id_spec[0] | std::views::split("\n"sv) | std::views::transform([](auto const& str) {
+        return std::ranges::fold_left(str | std::views::split("-"sv), std::vector<f64>{}, [](auto a, auto const& v) {
+                a.push_back(std::stod(std::string({std::begin(v), std::end(v)})));
+                return a;
+            });
+    }) | std::ranges::to<std::vector>();
+
+    auto ids = id_spec[1] | std::views::split("\n"sv) | std::views::transform([](auto const& str) {
+        return std::stod(std::string{std::begin(str), std::end(str)});
+    }) | std::ranges::to<std::vector>();
+
+    f64 sum = 0;
+
+    for (usize i = 0; i < ids.size(); ++i) {
+        auto const id = ids[i];
+        bool is_valid = false;
+        for (usize j = 0; j < id_range.size(); ++j) {
+            auto const a = id_range[j][0];
+            auto const b = id_range[j][1];
+
+            if (id >= a && id <= b) {
+                is_valid = true;
+                break;
+            }
+        }
+
+        fmt::print("id: {} is {}\n", id, is_valid ? "valid" : "not valid");
+
+        if (is_valid) ++sum;
+    }
+
+    fmt::print("res: {}\n", sum);
+}
+
+auto main([[maybe_unused]]int argc, [[maybe_unused]]char const* argv[]) -> int {
+    try {
+        entry({argv, std::next(argv, argc)});
+    } catch (std::exception const& e) {
+        fmt::print(stderr, "{}\n", e.what());
+        return 1;
+    }
+    return 0;
+}