diff --git a/backend/blog.go b/backend/blog.go
index e70ee74..6c86dd7 100644
--- a/backend/blog.go
+++ b/backend/blog.go
@@ -37,7 +37,7 @@ type Article struct {
 }
 
 type ArticleFile struct {
-	Id   int
+	Id   int64
 	Data []byte
 }
 
@@ -66,7 +66,7 @@ func ParseArticle(reader io.Reader, filePrefix string) (*Article, error) {
 	}
 
 	usedFiles := make(map[string]ArticleFile)
-	nextFileId := 0
+	nextFileId := int64(0)
 
 	pc, html, err := md.Parse(func(path string) (string, error) {
 		content, ok := tarFiles[strings.TrimPrefix(path, "./")]
@@ -77,7 +77,7 @@ func ParseArticle(reader io.Reader, filePrefix string) (*Article, error) {
 		usedFiles[path] = ArticleFile{nextFileId, content}
 		nextFileId++
 
-		return filePrefix + strconv.Itoa(nextFileId), nil
+		return filePrefix + strconv.FormatInt(nextFileId, 10), nil
 	}, readmeBytes)
 	if err != nil {
 		return nil, err