#define _CRT_SECURE_NO_WARNINGS
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <string.h>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#define rep(i,n) for(int i=0;i<(lint)(n);i++)
#define REP(i,n) for(int i=1;i<=(lint)(n);i++)
#define all(V) V.begin(),V.end()
#define stackReplaceBegin(size)\
	void* p=malloc(size);\
	esp_new=(lint)p+size-1;\
	void * stack_extend_memory_ = malloc(size);\
	void * stack_extend_origin_memory_;\
	char * stack_extend_dummy_memory_ = (char*)alloca((1+(int)(((long long)stack_extend_memory_)&127))*16);\
	*stack_extend_dummy_memory_ = 0;\
	asm volatile("mov %%rsp, %%rbx\nmov %%rax, %%rsp":"=b"(stack_extend_origin_memory_):"a"((char*)stack_extend_memory_+(size)-1024));
typedef long long lint;
typedef unsigned long long ulint;
typedef std::pair<int, int> P;
constexpr int INF = INT_MAX/2;
constexpr lint LINF = LLONG_MAX/2;
constexpr double eps = DBL_EPSILON;
constexpr double PI = 3.141592653589793238462643383279;
lint esp_new;
template<class T>
class prique :public std::priority_queue<T, std::vector<T>, std::greater<T>> {};
template <class T, class U>
inline bool chmax(T& lhs, const U& rhs) {
	if (lhs < rhs) {
		lhs = rhs;
		return 1;
	}
	return 0;
}
template <class T, class U>
inline bool chmin(T& lhs, const U& rhs) {
	if (lhs > rhs) {
		lhs = rhs;
		return 1;
	}
	return 0;
}
inline lint gcd(lint a, lint b) {
	while (b) {
		lint c = a;
		a = b; b = c % b;
	}
	return a;
}
inline lint lcm(lint a, lint b) {
	return a / gcd(a, b) * b;
}
bool isprime(lint n) {
	if (n == 1)return false;
	for (int i = 2; i * i <= n; i++) {
		if (n % i == 0)return false;
	}
	return true;
}
template<typename T>
T mypow(T a, unsigned int b) {
	T res(1),now(a);
	while(b){
		if(b&1)res*=now;
		b>>=1;
		now*=now;
	}
	return res;
}
lint modpow(lint a,unsigned int b,unsigned int mod){
	lint res(1),now(a%mod);
	while(b){
		if(b&1){
			res*=now;
			res%=mod;
		}
		b>>=1;
		now*=now;
		now%=mod;
	}
	return res;
}
template<typename T>
void printArray(std::vector<T>& vec) {
	rep(i, (int)vec.size() - 1)std::cout << vec[i] << " ";
	if(!vec.empty())std::cout << vec.back() << std::endl;
}
template<typename T>
void printArray(T l, T r) {
	T rprev = r;
	rprev--;
	for (T i = l; i != rprev; i++) {
		std::cout << *i << " ";
	}
	std::cout << *rprev << std::endl;
}
template<typename T>
class SegTree {
protected:
	unsigned int n = 1, rank = 0;
	std::vector<T> node;
	T nodee;
	virtual T nodef(const T&, const T&)const = 0;
public:
	SegTree(unsigned int m, T init, T nodee):nodee(nodee) {
		while (n < m) {
			n *= 2;
			rank++;
		}
		node.resize(2 * n);
		for (unsigned int i = n; i < 2 * n; i++)node[i] = init;
	}
	SegTree(const std::vector<T>& initvec, T nodee):nodee(nodee) {
		unsigned int m = initvec.size();
		while (n < m) {
			n *= 2;
			rank++;
		}
		node.resize(2 * n);
		for (unsigned int i = n; i < 2 * n; i++) {
			if (i - n < m)node[i] = initvec[i - n];
		}
	}
	virtual void update(int i, T x) {
		i += n;
		node[i] = x;
		while (i != 1) {
			i >>= 1;
			node[i] = nodef(node[2 * i], node[2 * i + 1]);
		}
	}
	virtual T query(int l, int r) {
		l += n; r += n;
		T ls = nodee, rs = nodee;
		while (l < r) {
			if (l & 1) {
				ls = nodef(ls, node[l]);
				l++;
			}
			if (r & 1) {
				r--;
				rs = nodef(node[r], rs);
			}
			l >>= 1; r >>= 1;
		}
		return nodef(ls, rs);
	}
	virtual T operator[](const int& x) {
		return node[n + x];
	}
	void fill(T x) {
		std::fill(all(node), x);
	}
	void print() {
		rep(i, n)std::cout << operator[](i) << " ";
		std::cout << std::endl;
	}
};
class RMiQ :public SegTree<lint> {
	lint nodef(const lint& lhs,const lint& rhs)const{return std::min(lhs,rhs);}
public:
	RMiQ(int size, const lint& def = 0) :SegTree<lint>(size, def, LINF) {}
	RMiQ(const std::vector<lint>& initvec) :SegTree<lint>(initvec, LINF) {}
};
int n,p[200010],d[200010];
std::set<int> interval,min;
int main(){
	std::cin>>n;
	std::vector<RMiQ> st(2,RMiQ(n,INF));
	rep(i,n){
		std::cin>>p[i];
		st[i%2].update(i,p[i]);
		d[p[i]]=i;
	}
	interval.insert(0);
	interval.insert(n);
	min.insert(st[0].query(0,n));
	std::vector<int> ans;
	rep(i,n/2){
		int x=*min.begin();
		ans.emplace_back(x);
		int l=d[x]+1,r=*interval.upper_bound(d[x]);
		int y=st[l%2].query(l,r);
		ans.emplace_back(y);
		l=*--interval.upper_bound(d[x]);
		st[d[x]%2].update(d[x],INF);
		st[d[y]%2].update(d[y],INF);
		min.erase(x);
		interval.insert(d[x]+1);
		interval.insert(d[y]+1);
		if(l!=d[x])min.insert(st[l%2].query(l,d[x]));
		if(d[x]+1!=d[y])min.insert(st[(d[x]+1)%2].query(d[x]+1,d[y]));
		if(d[y]+1!=r)min.insert(st[(d[y]+1)%2].query(d[y]+1,r));
	}
	printArray(ans);
	return 0;
}

Measured memory_bytes: 23176