#![allow(non_snake_case)]
use std::collections::BTreeSet;
use std::iter::once;
use proconio::{input};

fn main() {
    input!{ n: usize, p: [usize; n] }
    let mut index = vec![0; n];
    for i in 0..n { index[p[i] - 1] = i; }
    let mut unused: BTreeSet<_> = (0..n).collect();
    let mut next = (1..n).chain(once(usize::MAX)).collect::<Vec<_>>();
    let mut prev = once(usize::MAX).chain(0..n-1).collect::<Vec<_>>();
    let mut ans = Vec::new();
    while !unused.is_empty() {
        let target_index = {
            let mut iter = unused.iter();
            let min = iter.next().unwrap();
            let min_index = index[*min];
            if next[min_index] < n {
                min_index
            } else {
                let second_min = iter.next().unwrap();
                index[*second_min]
            }
        };
        let target1 = p[target_index] - 1;
        let target2 = p[next[target_index]] - 1;
        ans.push(target1 + 1);
        ans.push(target2 + 1);
        unused.remove(&target1);
        unused.remove(&target2);
        let prev_index = prev[target_index];
        let next_index = next[next[target_index]];
        if prev_index < n {
            next[prev_index] = next_index;
        }
        if next_index < n {
            prev[next_index] = prev_index;
        }
    }
    for x in ans { print!("{x} "); }
}