diff --git a/generator/src/util.rs b/generator/src/util.rs
index 8fee296..0a5f55b 100644
--- a/generator/src/util.rs
+++ b/generator/src/util.rs
@@ -1,14 +1,15 @@
-pub fn smallest_index(n: usize) -> usize {
-    for &x in [8, 16, 32].iter() {
-        if n < (1 << x) {
-            return x / 8;
+/// Figure out whether we need `u8` (1 byte), `u16` (2 bytes) or `u32` (4 bytes) to store all
+/// numbers. Returns the number of bytes
+pub fn smallest_type<I: Iterator<Item = u32>>(x: I) -> usize {
+    let n = x.max().unwrap_or(0);
+    for (max, bytes) in [(u8::MAX as u32, 1), (u16::MAX as u32, 2)] {
+        if n <= max {
+            return bytes;
         }
     }
-    64
-}
-pub fn smallest_type<I: Iterator<Item = u32>>(x: I) -> usize {
-    smallest_index(x.max().unwrap_or(0) as usize)
+    4
 }
+
 pub fn smallest_u<I: Iterator<Item = u32>>(x: I) -> String {
     format!("u{}", 8 * smallest_type(x))
 }