---
id: 5900f40a1000cf542c50ff1d
challengeType: 5
title: 'Problem 158: Exploring strings for which only one character comes lexicographically after its neighbour to the left'
videoUrl: ''
localeTitle: ''
---
## Description
undefined
## Instructions
undefined
## Tests
```yml
tests:
- text: ''
testString: 'assert.strictEqual(euler158(), 409511334375, "euler158() should return 409511334375.");'
```
## Challenge Seed
```js
function euler158() {
// Good luck!
return true;
}
euler158();
```