freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-186-connectedness-of-a-network.english.md

---
id: 5900f4281000cf542c50ff39
challengeType: 5
title: 'Problem 186: Connectedness of a network'
forumTopicId: 301822
---

## Description
<section id='description'>
Here are the records from a busy telephone system with one million users:

RecNrCallerCalled120000710005326001835004393600863701497.........
The telephone number of the caller and the called number in record n are Caller(n) = S2n-1 and Called(n) = S2n where S1,2,3,... come from the "Lagged Fibonacci Generator":

For 1 ≤ k ≤ 55, Sk = [100003 - 200003k + 300007k3] (modulo 1000000)
For 56 ≤ k, Sk = [Sk-24 + Sk-55] (modulo 1000000)

If Caller(n) = Called(n) then the user is assumed to have misdialled and the call fails; otherwise the call is successful.

From the start of the records, we say that any pair of users X and Y are friends if X calls Y or vice-versa. Similarly, X is a friend of a friend of Z if X is a friend of Y and Y is a friend of Z; and so on for longer chains.

The Prime Minister's phone number is 524287. After how many successful calls, not counting misdials, will 99% of the users (including the PM) be a friend, or a friend of a friend etc., of the Prime Minister?
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler186()</code> should return 2325629.
    testString: assert.strictEqual(euler186(), 2325629);

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler186() {
  // Good luck!
  return true;
}

euler186();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>