diff --git a/04-fibonacci/index.js b/04-fibonacci/index.js
index 34e2e43..f316e95 100644
--- a/04-fibonacci/index.js
+++ b/04-fibonacci/index.js
@@ -3,5 +3,11 @@ export function fibonacci(value) {
   if(value <= 1){
     return value
   }
-  return fibonacci(value - 1) + fibonacci(value - 2)
+  let v1 = 0, v2 = 1, v3 = 1;
+  for (let i = 2; i <= value ; i++) {
+    v3 = v1 + v2;
+    v1 = v2;
+    v2 = v3 
+  }
+  return v3;
 }