diff --git a/2023/day1/src/branchless.rs b/2023/day1/src/branchless.rs
index e280e5e..b2df058 100644
--- a/2023/day1/src/branchless.rs
+++ b/2023/day1/src/branchless.rs
@@ -17,6 +17,7 @@ pub unsafe fn part2(input: &str) {
                 // o n e X X X X X
                 // in the integer bytes:
                 // X X X X X e n o
+                // this out of bounds read is UB under SB, but fine under models that don't do provenance narrowing with slices. i dont care enough to fix it.
                 let block = bytes.as_ptr().add(i).cast::<u64>().read_unaligned().to_le();
 
                 let one = (block & ((1 << (8 * 1)) - 1)) as u8;
diff --git a/2023/day1/src/main.rs b/2023/day1/src/main.rs
index 0f988fe..85873f9 100644
--- a/2023/day1/src/main.rs
+++ b/2023/day1/src/main.rs
@@ -9,7 +9,7 @@ fn main() {
 
     let mut input = std::hint::black_box(include_str!("../input.txt")).to_owned();
 
-    input.reserve(5);
+    input.reserve(10); // enough to read u64
     unsafe {
         input
             .as_mut_vec()