Count Primes Up to N — Level 1

In the neon-drenched streets of Neo-Codelin, the megacorporation ByteCorp has issued a desperate bounty. Their central mainframe has been flooded with raw data, and only an independent hacker of the Pixel Pusher tier can process it before the city's infrastructure collapses. The rain pounds against the windows of a small apartment where the runner known only as Cipher prepares for the job. The contract is for a problem code-named "Count Primes Up to N — Level 1". Cipher jacks into the matrix and pulls up the brief. The screen glows with blue light, reflecting in her mirrored shades. Read an integer n and print the count of prime numbers from 2 to n. The contract terms are strict. Failure is not an option, and the constraints are non-negotiable: 0 <= n <= 1000 To verify the payload, Cipher runs these test fragments through her neural link: Input: 10 Output: 4 The clock is ticking. ByteCorp's automated defense drones are already closing in on her location. Write a solution that is clean, fast, and correct. The future of Neo-Codelin — and Cipher's survival — depends on it. The path to mastering Count Primes Up to N — Level 1 is not one that can be walked in a single step. It demands patience, precision, and a deep respect for the boundaries that shape the problem. Many adventurers before you have attempted this trial and failed, their code crashing against the very constraints that the elders inscribed. But you have the tools. You have the training. You have reached the Pixel Pusher tier, and that alone means the council believes in your potential. Look once more at the examples above. Trace the logic with your finger if you must. Consider the time and memory limits carefully, for they are not suggestions but strict laws of the arena. When you are ready, commit your solution. Let the compiler run. Let the test cases judge your work. If your code is true, the gates will open and you will move closer to the ultimate rank. If not, study the failure, sharpen your algorithm, and try again. For in the halls of CodeTikki, the only thing more important than success is the wisdom gained from the attempt. Remember that the Pixel Pusher challenge is designed to test not just knowledge, but character. Every edge case is a lesson. Every time limit is a teacher. Every hidden test is a guardian at the gate. Do not rush. Let your code breathe. Let it be as clean as a mountain stream. When the final test passes, you will know that you have earned the title. Until then, code with courage, test with care, and never stop learning.