# include <iostream>
# include <algorithm>
#include <array>
# include <cassert>
#include <cctype>
#include <climits>
#include <numeric>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <tuple>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <bitset>
# include <complex>
# include <chrono>
# include <random>
# include <limits.h>
# include <unordered_map>
# include <unordered_set>
# include <deque>
# include <cstdio>
# include <cstring>
#include <stdio.h>
#include<time.h>
#include <stdlib.h>
#include <cstdint>
#include <cfenv>
#include<fstream>
//#include <bits/stdc++.h>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
long long MOD = 1000000000 + 7;// 998244353;// ;
constexpr long long INF = numeric_limits<LL>::max() / 2;
const double PI = acos(-1);
#define fir first
#define sec second
#define thi third
#define debug(x) cerr<<#x<<": "<<x<<'\n'
typedef pair<LL, LL> Pll;
typedef pair<LL, pair<LL, LL>> Ppll;
typedef pair<LL, pair<LL, bitset<100001>>> Pbll;
typedef pair<LL, pair<LL, vector<LL>>> Pvll;
typedef pair<LL, LL> Vec2;
struct Tll { LL first, second, third; };
struct Fll { LL first, second, third, fourd; };
typedef pair<LL, Tll> Ptll;
#define rep(i,rept) for(LL i=0;i<rept;i++)
#define Rrep(i,mf) for(LL i=mf-1;i>=0;i--)
void YN(bool f) {
	if (f)
		cout << "YES" << endl;
	else
		cout << "NO" << endl;
}
void yn(bool f) {
	if (f)
		cout << "Yes" << endl;
	else
		cout << "No" << endl;
}
struct Edge { LL to, cost; };
struct edge { LL from, to, cost; };
vector<vector<LL>>g;
vector<edge>edges;
vector<LL>v;
map<LL, LL>ma;
set<Pll>st;
LL h, w, n, m, k, t, s, p, q, last, cnt, sum, ans[210000], dp[210000], a[210000], b[210000];
string str, ss;
bool f;
char c;
struct Seg {
	LL n;
	vector<LL>node;
	Seg(LL n_) {
		n = 1; while (n < n_)n *= 2;
		node.resize(n * 2 - 1);
		rep(i, n*2-1)node[i] = INF;
	}
	void update(LL i, LL x) {
		i = i + n - 1;
		node[i] = x;
		while (i > 0) {
			i = (i - 1) / 2;
			node[i] = min(node[i * 2 + 1], node[i * 2 + 2]);
		}
	}
	LL find(LL l, LL r) {
		return find(0, 0, n - 1, l, r);
	}
	LL find(LL i, LL a, LL b, LL l, LL r) {
		if (b < l || r < a)return INF;
		if (l <= a && b <= r)return node[i];
		return min(find(i * 2 + 1, a, (a + b) / 2, l, r), find(i * 2 + 2, (a + b + 1) / 2, b, l, r));
	}
};
Seg seg1(210000), seg2(210000);
Pll node[210000];
int main() {
	cin >> n;
	g.resize(n / 2);
	rep(i, n) {
		cin >> a[i];
		b[a[i]] = i;
		if (i % 2 == 0)
			seg1.update(i, a[i]);
		else
			seg2.update(i, a[i]);
	}
	queue<Ppll>qu;
	qu.push(Ppll(0, Pll(n - 1, -1)));
	while (!qu.empty()) {
		Pll cur = Pll(qu.front().first, qu.front().second.first);
		LL u = qu.front().second.second;
		qu.pop();
		LL l, r;
		if (cur.first % 2 == 0) {
			l = seg1.find(cur.first, cur.second);
			r = seg2.find(b[l], cur.second);
		}
		else {
			l = seg2.find(cur.first, cur.second);
			r = seg1.find(b[l], cur.second);
		}
		node[cnt] = Pll(l, r);
		if (u != -1) {
			g[u].push_back(cnt);
		}
		l = b[l];
		r = b[r];
		if (cur.first != l)
			qu.push(Ppll(cur.first, Pll(l - 1, cnt)));
		if (l + 1 < r - 1)
			qu.push(Ppll(l + 1, Pll(r - 1, cnt)));
		if (cur.second != r)
			qu.push(Ppll(r + 1, Pll(cur.second, cnt)));
		cnt++;
	}
	priority_queue<Pll, vector<Pll>, greater<Pll>>pq;
	pq.push(Pll(node[0].first, 0));
	vector<LL>V;
	while (!pq.empty()) {
		Pll cur = pq.top();
		LL v = cur.second;
		pq.pop();
		V.push_back(node[v].first);
		V.push_back(node[v].second);
		rep(i, g[v].size()) {
			pq.push(Pll(node[g[v][i]].first, g[v][i]));
		}
	}
	rep(i, n) {
		if (i)cout << " ";
		cout << V[i];
	}
	cout << endl;
	return 0;
}

Measured memory_bytes: 24560