diff --git a/src/prerelease.rs b/src/prerelease.rs
index 085e877..20e5b24 100644
--- a/src/prerelease.rs
+++ b/src/prerelease.rs
@@ -30,56 +30,57 @@ impl str::FromStr for PreRelease {
     type Err = Error;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let max = unsafe { NonZeroU16::new_unchecked(1025) };
         match s {
             "Alpha" | "alpha" => Ok(Self::Alpha(None)),
             "Beta" | "beta" => Ok(Self::Beta(None)),
             "RC" | "Rc" | "rc" => Ok(Self::RC(None)),
             s if s.starts_with("Alpha") => {
                 let suf = s.strip_prefix("Alpha").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::Alpha(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::Alpha(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("alpha") => {
                 let suf = s.strip_prefix("alpha").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::Alpha(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::Alpha(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("Beta") => {
                 let suf = s.strip_prefix("Beta").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::Beta(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::Beta(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("beta") => {
                 let suf = s.strip_prefix("beta").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::Beta(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::Beta(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("RC") => {
                 let suf = s.strip_prefix("RC").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::RC(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::RC(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("Rc") => {
                 let suf = s.strip_prefix("Rc").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::RC(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::RC(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }
             s if s.starts_with("rc") => {
                 let suf = s.strip_prefix("rc").unwrap();
-                match suf.parse::<u16>() {
-                    Ok(v) if v > 0 && v < 1025 => Ok(Self::RC(Some(v.try_into()?))),
+                match suf.parse() {
+                    Ok(v) if v < max => Ok(Self::RC(Some(v))),
                     _ => Err(Error::ParsePreRelease),
                 }
             }