diff --git a/10_fibonacci/fibonacci.js b/10_fibonacci/fibonacci.js
index bb2c8cc..5e4a3c7 100644
--- a/10_fibonacci/fibonacci.js
+++ b/10_fibonacci/fibonacci.js
@@ -1,5 +1,11 @@
-const fibonacci = function() {
+const fibonacci = function(n) {
+    n = +n;
+    if(n<0) return 'OOPS';
 
+    if(n == 1 || n == 2){
+        return 1;
+    }
+    return(fibonacci(n-1)+fibonacci(n-2));
 };
 
 // Do not edit below this line