**PROBLEM LINK:**

**Author:** Manish Pathak

**Tester:** Manish Pathak

**Editorialist:** Manish Pathak

**DIFFICULTY:**

Cakewalk

**PROBLEM:**

In a bungalow a person found a dead body and informed the police to investigate the matter. Police thought that it would be better to give this case to CBI.CBI team came and found a code. To decode that they want a specialized person,Chef is a right person for this work but he is busy these days so you have to do this job.

Your task is to count the number of **digit one** in all non-negative integers less than or equal to **N** .

**EXPLANATION:**

Brute force approach to do this problem is to calculate the number of 1’s in each and every number <=N.As the testcases were weak so this will work.

**AUTHOR’S AND EDITORIALIST’S SOLUTIONS:**

Author’s and editorialist’s solution can be found here