diff --git a/src/main/java/com/ets/scraper/EtsScraper.java b/src/main/java/com/ets/scraper/EtsScraper.java
index a8fb2d1..14f7e42 100644
--- a/src/main/java/com/ets/scraper/EtsScraper.java
+++ b/src/main/java/com/ets/scraper/EtsScraper.java
@@ -58,7 +58,18 @@ public class EtsScraper {
                     dateStr = args[++i];
                     break;
                 case "-r":
-                    repeatInterval = Integer.parseInt(args[++i]);
+                    if (i + 1 >= args.length) {
+                        System.err.println("[-] -r requires an argument");
+                        printHelp();
+                        return;
+                      }
+                    try {
+                        repeatInterval = Integer.parseInt(args[++i]);
+                      } catch (NumberFormatException e) {
+                        System.err.println("[-] -r must be a positive integer");
+                        printHelp();
+                        return;
+                      }
                     break;
                 default:
                     System.err.println("[-] Unknown option: " + args[i]);