I don't know the problem

use std::io;
use std::io::BufReader;
use std::io::BufRead;
fn minimal_product_digit(n: i64) -> i64{
    if n == 0 {return 10};
    if n < 10 { return n};

    let f : Vec<i64> = vec![2,3,5,7];
    let mut aux = n;
    let mut ret : Vec<i64> = Vec::new();
    for i in f{

        if  aux % i== 0 {

            loop{
                aux/=i;
                 ret.push(i);
                if aux % i != 0 {
                    break;
                }
            }
        }
    };

    if ret.is_empty() || aux > 1 {
        return -1;
    }

    match ret.iter().fold(0,|acc,elem| if *elem == 3{acc + 1} else {acc}) {

        1 => {

            let index = ret .iter().position(|&x| x == 3).unwrap();

            if index > 0{

                ret.remove(index);

                let k = ret.get_mut(index - 1).unwrap();

                *k = 6;

                ret.sort();

            }
        }

        _ => ()

    }
    let mut v : Vec<i64> = Vec::new();
    for i in ret{

        match i {

            2 | 3=>

                match v.last_mut(){

                    None => v.push(i),
                    Some(last) if i ==3 && *last == 2 => v.push(i),
                    Some(last) => {
                        let valor = *last;
                        if (valor * i) < 10{
                            *last = valor*i
                        }
                        else{
                            v.push(i);
                        }
                    }
                }
            _ => v.push(i)
        }
    }

        v.sort();
        v.iter().fold(0, |acc, elem| acc * 10 + elem)

}

fn main() {

    let mut line = String::new();
    let mut stdin = BufReader::new(io::stdin());

  stdin.read_line(&mut line).unwrap();

    let lim = line.trim().parse::<i64>().unwrap();

    println!("{:?}",minimal_product_digit(lim));

}