use std::env;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() != 2 {
        println!("Usage: ./primes $MAX");
        return;
    }
    let max: u64 = args[1].parse().expect("MAX must be an integer value");
    let mut i: u64 = 3;
    
    while i <= max {        
        let loop_max: u64 = (i as f64).sqrt() as u64;
        let mut x: u64 = 2;
        let mut prime = true;
        while x <= loop_max {
            if i % x == 0 {                
                prime = false;
                break;
            }
            x += 1;
        }
        if prime {
            println!("{}", i)
        }
        i += 2;
    }
}