diff --git a/README.md b/README.md
index f5fb0a1..e5fab4c 100644
--- a/README.md
+++ b/README.md
@@ -75,7 +75,7 @@ implementations compare to each other.
 | grep | 0m18.034s | 0m15.713s | 0m2.257s |
 | ripgrep | 0m1.709s | 0m1.541s | 0m0.147s |
 | simple (Go) | 0m1.889s | 0m1.679s | 0m0.211s |
-| simple (Rust) | 0m2.169s | 0m1.943s | 0m0.219s |
+| simple (Rust) | 0m1.623s | 0m1.415s | 0m0.204s |
 | simple (Node) | 0m6.458s | 0m6.043s | 0m0.627s |
 | custom (C) | **0m0.222s** | **0m0.079s** | **0m0.141s** |
 
diff --git a/main.rs b/main.rs
index 87b13c6..f9540b6 100644
--- a/main.rs
+++ b/main.rs
@@ -26,7 +26,7 @@ fn scan_slice(inb: &[u8]) -> usize {
 	let mut count = 0;
 	let len = inb.len();
 	for (i, &b) in inb.into_iter().enumerate() {
-		if b >= b'0' && b <= b'9' || b >= b'a' && b <= b'f' {
+		if b.is_ascii_digit() || (b'a'..=b'f').contains(&b) {
 			count += 1;
 			continue
 		}