FromStr has not been released
diff --git a/README.md b/README.md
index c7650f7..6273b44 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@
     let source = input.to_string();
 
     // Parse the string representation into a syntax tree
-    let ast: syn::DeriveInput = source.parse().unwrap();
+    let ast = syn::parse_derive_input(&source).unwrap();
 
     // Build the output, possibly using quasi-quotation
     let expanded = quote! {
@@ -81,7 +81,7 @@
     let source = input.to_string();
 
     // Parse the string representation into a syntax tree
-    let ast: syn::DeriveInput = source.parse().unwrap();
+    let ast = syn::parse_derive_input(&source).unwrap();
 
     // Build the output
     let expanded = expand_num_fields(&ast);