diff --git a/package-lock.json b/package-lock.json
index f356890..a1adbfd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,7 @@
         "jest": "^29.3.1",
         "supertest": "^6.3.3",
         "ts-jest": "^29.0.5",
-        "typescript": "^4.9.4"
+        "typescript": "^4.9.5"
       }
     },
     "node_modules/@ampproject/remapping": {
@@ -5495,9 +5495,9 @@
       }
     },
     "node_modules/typescript": {
-      "version": "4.9.4",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-4.9.4.tgz",
-      "integrity": "sha512-Uz+dTXYzxXXbsFpM86Wh3dKCxrQqUcVMxwU54orwlJjOpO3ao8L7j5lH+dWfTwgCwIuM9GQ2kvVotzYJMXTBZg==",
+      "version": "4.9.5",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-4.9.5.tgz",
+      "integrity": "sha512-1FXk9E2Hm+QzZQ7z+McJiHL4NW1F2EzMu9Nq9i3zAaGqibafqYwCVU6WyWAuyQRRzOlxou8xZSyXLEN8oKj24g==",
       "dev": true,
       "bin": {
         "tsc": "bin/tsc",
diff --git a/package.json b/package.json
index b108afa..35c8370 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
     "jest": "^29.3.1",
     "supertest": "^6.3.3",
     "ts-jest": "^29.0.5",
-    "typescript": "^4.9.4"
+    "typescript": "^4.9.5"
   },
   "dependencies": {
     "express": "^4.17.1"
diff --git a/src/fib.ts b/src/fib.ts
index 0d292e9..787ef63 100644
--- a/src/fib.ts
+++ b/src/fib.ts
@@ -1,5 +1,5 @@
 // util function that computes the fibonacci numbers
-export default function fibonacci(n) {
+export default function fibonacci(n:number) {
   if (n < 0) {
     return -1;
   } else if (n == 0) {