diff --git a/src/days/day04.zig b/src/days/day04.zig
index 261c31e..cca3d1a 100644
--- a/src/days/day04.zig
+++ b/src/days/day04.zig
@@ -2,7 +2,7 @@ const std = @import("std");
 
 pub const title = "Day 04: Printing Department";
 
-pub fn run(_: std.mem.Allocator) !void {
+pub fn run(allocator: std.mem.Allocator) !void {
     const initial_input = @embedFile("./input/day04.txt");
     //const initial_input =
     //    \\..@@.@@@@.
@@ -17,7 +17,9 @@ pub fn run(_: std.mem.Allocator) !void {
     //    \\@.@.@@@.@.
     //    ;
 
-    const input: []u8 = @constCast(initial_input);
+    const input = try allocator.alloc(u8, initial_input.len);
+    defer allocator.free(input);
+    @memcpy(input, initial_input);
 
     var accumulator: u32 = 0;