use std::env::args;
use std::iter::{once, repeat};
fn main() {
let max_depth = args()
.skip(1)
.next()
.and_then(|arg| arg.parse().ok())
.unwrap_or(8);
let out: String = (1..=max_depth)
.flat_map(|i| {
repeat(' ')
.take(max_depth - i)
.chain(repeat('*').take(i * 2 - 1))
.chain(once('\n'))
})
.collect();
print!("{}", out);
}