Inverted half pyramid of numbers in rust

inverted-half-pyramid-of-numbers.rs

use std::io;

fn main(){

    let mut rows = String::new();
    io::stdin()
        .read_line(&mut rows)
        .expect("failed to readline");

    let row = rows.trim().parse::<i64>().unwrap();

    for n in (0..row+1).rev() { 
        for mut y in (1..n+1) { 
            print!("{y}");
        }
        print!("\n");
    }
}

An example of the output:

12345
1234
123
12
1