diff --git a/assignments/bmi_calculator/bmi_calculator.js b/assignments/bmi_calculator/bmi_calculator.js
index 0cdd351..ffeaa49 100644
--- a/assignments/bmi_calculator/bmi_calculator.js
+++ b/assignments/bmi_calculator/bmi_calculator.js
@@ -1,6 +1,13 @@
 // This function should return the BMI for a person 
 function BMICalculator(mass, height) {
     // Write your code here
+    if(mass>0 && height>0){
+        BMI = mass / (height * height)
+        return BMI
+    }
+    else{
+        return "INVALID INPUT";
+    }
 }
 
 module.exports = BMICalculator;