You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: shootout-regex-dna-single.rs
    path of file: ./repos/phaser/phaser/vendor/regex/examples
    
    the code of the file until where you have to start completion: // The Computer Language Benchmarks Game
// https://benchmarksgame-team.pages.debian.net/benchmarksgame/
//
// contributed by the Rust Project Developers
// contributed by TeXitoi
// contributed by BurntSushi

use std::io::{self, Read};

macro_rules! regex {
    ($re:expr) => {
        ::regex::Regex::new($re).unwrap()
    };
}

fn main() {
    let mut seq = String::with_capacity(50 * (1 << 20));
    io::stdin().read_to_string(&mut seq).unwrap();
    let ilen = seq.len();

    seq = regex!(">[^\n]*\n|\n").replace_all(&seq, "").into_owned();
    let clen = seq.len();

    let variants = vec![
        regex!("agggtaaa|tttaccct"),
        regex!("[cgt]gggtaaa|tttaccc[acg]"),
        regex!("a[act]ggtaaa|tttacc[agt]t"),
        regex!("ag[act]gtaaa|tttac[agt]ct"),
        regex!("agg[act]taaa|ttta[agt]cct"),
        regex!("aggg[acg]aaa|ttt[cgt]ccct"),
        regex!("agggt[cgt]aa|tt[acg]accct"),
        regex!("agggta[cgt]a|t[acg]taccct"),
        regex!("agggtaa[cgt]|[acg]ttaccct"),
    ];
    for re in variants {
        println!("{} {}", re.to_stri
    
fn main() {
    let mut seq = String::with_capacity(50 * (1 << 20));
    io::stdin().read_to_string(&mut seq).unwrap();
    let ilen = seq.len();

    seq = regex!(">[^\n]*\n|\n").replace_all(&seq, "").into_owned();
    let clen = seq.len();

    let variants = vec![
        regex!("agggtaaa|tttaccct"),
        regex!("[cgt]gggtaaa|tttaccc[acg]"),
        regex!("a[act]ggtaaa|tttacc[agt]t"),
        regex!("ag[act]gtaaa|tttac[agt]ct"),
        regex!("agg[act]taaa|ttta[agt]cct"),
        regex!("aggg[acg]aaa|ttt[cgt]ccct"),
        regex!("agggt[cgt]aa|tt[acg]accct"),
        regex!("agggta[cgt]a|t[acg]taccct"),
        regex!("agggtaa[cgt]|[acg]ttaccct"),
    ];
    for re in variants {
        println!("{} {}", re.to_string(), re.find_iter(&seq).count());
    }

    let substs = vec![
        (regex!("B"), "(c|g|t)"),
        (regex!("D"), "(a|g|t)"),
        (regex!("H"), "(a|c|t)"),
        (regex!("K"), "(g|t)"),
        (regex!("M"), "(a|c)"),
        (regex!("N"), "(a|c|g|t)"),
        (regex!("R"), "(a|g)"),
        (regex!("S"), "(c|g)"),
        (regex!("V"), "(a|c|g)"),
        (regex!("W"), "(a|t)"),
        (regex!("Y"), "(c|t)"),
    ];
    let mut seq = seq;
    for (re, replacement) in substs {
        seq = re.replace_all(&seq, replacement).into_owned();
    }
    println!("\n{}\n{}\n{}", ilen, clen, seq.len());
}