diff --git a/lib/upn.js b/lib/upn.js
index 0ab33bf..0365ad5 100644
--- a/lib/upn.js
+++ b/lib/upn.js
@@ -1,6 +1,4 @@
-function upn() {
-  //
-}
+function upn() {}
 
 const multipliers = [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];
 
@@ -9,12 +7,10 @@ const letters = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
 
 function calculateScore(input) {
   const total = input.split('').reduce((accumulator, part, index) => {
-    const number = parseInt(part, 10);
-
-    return accumulator + (number * multipliers[index]);
+    return accumulator + (parseInt(part) * multipliers[index]);
   }, 0);
 
-  return total % 23;
+  return total % letters.length;
 }
 
 upn.prototype.validate = (input) => {
@@ -28,10 +24,8 @@ upn.prototype.validate = (input) => {
 };
 
 upn.prototype.generate = () => {
-  const number = `${Math.round(Math.random() * 1000000000000)}`;
-  const letter = letters[calculateScore(number)];
-
-  return `${letter}${number}`;
+  const number = `${Math.round(Math.random() * 1000000000000)}`
+  return `${letters[calculateScore(number)]}${number}`;
 };
 
 module.exports = upn;