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+/// --- Part Two ---
+///
+/// Your device's communication system is correctly detecting packets, but still isn't working.  It
+/// looks like it also needs to look for messages.
+///
+/// A start-of-message marker is just like a start-of-packet marker, except it consists of 14
+/// distinct characters rather than 4.
+///
+/// Here are the first positions of start-of-message markers for all of the above examples:
+///
+///     mjqjpqmgbljsphdztnvjfqwrcgsmlb: first marker after character 19
+///     bvwbjplbgvbhsrlpgdmjqwftvncz: first marker after character 23
+///     nppdvjthqldpwncqszvftbrmjlhg: first marker after character 23
+///     nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg: first marker after character 29
+///     zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw: first marker after character 26
+///
+/// How many characters need to be processed before the first start-of-message marker is detected?
+use clap::Parser;
+use itertools::Itertools;
+
+use std::fs::File;
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::iter::*;
+use std::path::PathBuf;
+
+const FILEPATH: &'static str = "examples/input.txt";
+const CONS_CHARS: usize = 14;
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+struct Cli {
+    #[clap(short, long, default_value = FILEPATH)]
+    file: PathBuf,
+}
+
+fn main() {
+    let args = Cli::parse();
+
+    let file = File::open(&args.file).unwrap();
+    let reader = BufReader::new(file);
+    let line = reader.lines().next().unwrap().unwrap();
+    let res = line
+        .into_bytes()
+        .windows(CONS_CHARS)
+        .position(|b| b.iter().all_unique())
+        .unwrap()
+        + CONS_CHARS;
+
+    println!("{:?}", res);
+}