**PROBLEM LINKS:**

**Difficulty:**

Easy

**Pre-requirements:**

Decimal-Octal conversion

**Problem:**

Find the frequence of digit **5** in the octal representation of the given decimal number **N**.

**1**<=**N**<=**10 ^{18}**

**Explanation:**

The digits in the octal representation can be easily obtained by continously dividing by 8 and finding the remainder till **N** becomes **Zero**. Remainder in each iteration represents a digit in octal representation.

Use a **count** variable to count the number of times the remainder is **5**

complexity: **O(log(N))**

**Authors Solution:**

can be found here