diff --git a/src/index.ts b/src/index.ts
index 009cca3..97c15b2 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,5 @@
 import { readLines } from "https://deno.land/std@0.87.0/io/bufio.ts";
+import { ValidationError } from "./errors/exceptions.ts";
 import { ID } from "./types/id.ts";
 import { sayHello, sayRandomHello } from "./usecases/hello.ts";
 
@@ -17,8 +18,16 @@ const start = async () => {
     } else if (value === "quit") {
       return;
     } else {
-      const id = new ID(parseInt(value, 10));
-      console.log(sayHello(id));
+      try {
+        const id = new ID(parseInt(value, 10));
+        console.log(sayHello(id));
+      } catch (error) {
+        if (error instanceof ValidationError) {
+          console.error(error.message);
+        } else {
+          throw error;
+        }
+      }
     }
   }
 };