// need
#include <iostream>
#include <algorithm>

// data structure
#include <bitset>
//#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
//#include <array>
//#include <tuple>
//#include <unordered_map>
//#include <unordered_set>
#include <complex>
//#include <deque>
#include<valarray>

// stream
//#include <istream>
//#include <sstream>
//#include <ostream>
#include <fstream>

// etc
#include <cmath>
#include <cassert>
#include <functional>
#include <iomanip>
//#include <typeinfo>
#include <chrono>
#include <random>
#include <numeric>


#define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
#define VAR(type, ...)type __VA_ARGS__;MACRO_VAR_Scan(__VA_ARGS__);
template<typename T> void MACRO_VAR_Scan(T& t) { std::cin >> t; }
template<typename First, typename...Rest>void MACRO_VAR_Scan(First& first, Rest&...rest) { std::cin >> first; MACRO_VAR_Scan(rest...); }
#define VEC_ROW(type, n, ...)std::vector<type> __VA_ARGS__;MACRO_VEC_ROW_Init(n, __VA_ARGS__); for(int i=0; i<n; ++i){MACRO_VEC_ROW_Scan(i, __VA_ARGS__);}
template<typename T> void MACRO_VEC_ROW_Init(int n, T& t) { t.resize(n); }
template<typename First, typename...Rest>void MACRO_VEC_ROW_Init(int n, First& first, Rest&...rest) { first.resize(n); MACRO_VEC_ROW_Init(n, rest...); }
template<typename T> void MACRO_VEC_ROW_Scan(int p, T& t) { std::cin >> t[p]; }
template<typename First, typename...Rest>void MACRO_VEC_ROW_Scan(int p, First& first, Rest&...rest) { std::cin >> first[p]; MACRO_VEC_ROW_Scan(p, rest...); }
#define OUT(d) std::cout<<d;
#define FOUT(n, d) std::cout<<std::fixed<<std::setprecision(n)<<d;
#define SOUT(n, c, d) std::cout<<std::setw(n)<<std::setfill(c)<<d;
#define SP std::cout<<" ";
#define TAB std::cout<<"\t";
#define BR std::cout<<"\n";
#define SPBR(i, n) std::cout<<(i + 1 == n ? '\n' : ' ');
#define ENDL std::cout<<std::endl;
#define FLUSH std::cout<<std::flush;
#define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
#define MAT(type, c, m, n) std::vector<std::vector<type>> c(m, std::vector<type>(n));for(auto& r:c)for(auto& i:r)std::cin>>i;
#define ALL(a) (a).begin(),(a).end()
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define RFOR(i, a, b) for(int i=(b)-1;i>=(a);--i)
#define REP(i, n) for(int i=0;i<int(n);++i)
#define RREP(i, n) for(int i=(n)-1;i>=0;--i)
#define FORLL(i, a, b) for(ll i=ll(a);i<ll(b);++i)
#define RFORLL(i, a, b) for(ll i=ll(b)-1;i>=ll(a);--i)
#define REPLL(i, n) for(ll i=0;i<ll(n);++i)
#define RREPLL(i, n) for(ll i=ll(n)-1;i>=0;--i)
#define IN(a, x, b) (a<=x && x<b)
#define SHOW(d) {std::cerr << #d << "\t:" << d << "\n";}
#define SHOWVECTOR(v) {std::cerr << #v << "\t:";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOWVECTOR2(v) {std::cerr << #v << "\t:\n";for(const auto& xxx : v){for(const auto& yyy : xxx){std::cerr << yyy << " ";}std::cerr << "\n";}}
#define SHOWQUEUE(a) {auto tmp(a);std::cerr << #a << "\t:";while(!tmp.empty()){std::cerr << tmp.front() << " ";tmp.pop();}std::cerr << "\n";}
template<typename T> inline T CHMAX(T& a, const T b) { return a = (a < b) ? b : a; }
template<typename T> inline T CHMIN(T& a, const T b) { return a = (a > b) ? b : a; }
#define EXCEPTION(msg) throw std::string("Exception : " msg " [ in ") + __func__ + " : " + std::to_string(__LINE__) + " lines ]"
#define TRY(cond, msg) try {if (cond) EXCEPTION(msg);}catch (std::string s) {std::cerr << s << std::endl;}
void CHECKTIME(std::function<void()> f) { auto start = std::chrono::system_clock::now(); f(); auto end = std::chrono::system_clock::now(); auto res = std::chrono::duration_cast<std::chrono::nanoseconds>((end - start)).count(); std::cerr << "[Time:" << res << "ns  (" << res / (1.0e9) << "s)]\n"; }

template<typename S, typename T>
std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
	os << "(" << p.first << ", " << p.second << ")";
	return os;
}

//#define int ll
using ll = long long;
using ull = unsigned long long;
using PAIR = std::pair<int, int>;
using PAIRLL = std::pair<ll, ll>;
constexpr int INFINT = 1 << 30;                          // 1.07x10^ 9
constexpr int INFINT_LIM = (1LL << 31) - 1;              // 2.15x10^ 9
constexpr ll INFLL = 1LL << 60;                          // 1.15x10^18
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);  // 9.22x10^18
constexpr double EPS = 1e-7;
constexpr int MOD = 1000000007;
constexpr double PI = 3.141592653589793238462643383279;

//SegmentTree(セグ木)
template <class T>
class SegmentTree {
private:
	T init_val;
	std::vector<T> ary;
	std::function<T(T, T)> func;
public:
	// 使用例(データの大きさNとする)
	// SegmentTree<T> st(N,  INF, [](T l, T r){return std::min(l, r);}); 最小値
	// SegmentTree<T> st(N, -INF, [](T l, T r){return std::max(l, r);}); 最大値
	// SegmentTree<T> st(N,    0, [](T l, T r){return l+r;});            合計
	SegmentTree(int n, T val, std::function<T(T, T)> f) : init_val(val), func(f) {
		ary.resize(static_cast<int>(std::pow(2, std::ceil(std::log(n) / std::log(2)) + 1) - 1), val);
	}
	void init(int n, T val, std::function<T(T, T)> f) {
		ary.resize(static_cast<int>(std::pow(2, std::ceil(1.0*std::log(n) / std::log(2)) + 1) - 1), val);
		init_val = val;
		func = f;
	}
	void update(int i, T val) {
		i += ary.size() / 2;
		ary[i] = val;
		while (i > 0) {
			i = (i - 1) / 2;
			ary[i] = func(ary[2 * i + 1], ary[2 * i + 2]);
		}
	}
	// 区間[a, b)のfuncの返す値を返す (query_(a, b, 0, 0, n)と呼び出す)
	T query_(int a, int b, int i, int l, int r) {
		if (r <= a || b <= l) return init_val;
		if (a <= l && r <= b) return ary[i];
		else {
			T vl = query_(a, b, 2 * i + 1, l, (l + r) / 2);
			T vr = query_(a, b, 2 * i + 2, (l + r) / 2, r);
			return func(vl, vr);
		}
	}
	// 上限(b)は少し大きめに取るべし
	T query(int a, int b) {
		return query_(a, b, 0, 0, ary.size() / 2 + 1);
	}
};

signed main() {
	INIT;
	VAR(int, n);
	VEC(int, p, n);
	std::vector<int> inv(n);

	REP(i, n) {
		--p[i];
		inv[p[i]] = i;
	}
	SegmentTree<int> odd(n, INFINT, [](int l, int r) {return std::min(l, r); }), even(n, INFINT, [](int l, int r) {return std::min(l, r); });

	REP(i, n) {
		if (i % 2 == 0) {
			odd.update(i, p[i]);
		}
		else {
			even.update(i, p[i]);
		}
	}

	auto calc = [&](PAIR p) {
		int l = p.first, r = p.second;
		if (l >= r) return PAIR(-1, -1);
		int minL, minR;
		int posL;
		if (l % 2 == 0) {
			minL = odd.query(l, r+1);
			posL = inv[minL];
			minR = even.query(posL+1, r+1);
		}
		else {
			minL = even.query(l, r+1);
			posL = inv[minL];
			minR = odd.query(posL+1, r+1);
		}
		return PAIR(minL, minR);
	};

	struct P {
		int l, r, ml, mr;
		P() {}
		P(int l, int r, int ml, int mr) :l(l), r(r), ml(ml), mr(mr){}
		bool operator<(const P rr) const {
			return ml > rr.ml;
		}
	};
	std::priority_queue<P> pq;
	{
		PAIR min(calc(PAIR(0, n - 1)));
		pq.push(P(0, n - 1, min.first, min.second));
	}
	while (!pq.empty()) {
		P now;
		while (!pq.empty()) {
			now = pq.top(); pq.pop();
			if (now.l >= now.r) continue;
			break;
		}
		if (now.l >= now.r) break;
		OUT(now.ml + 1)SP OUT(now.mr + 1)SP;
		int posL = inv[now.ml];
		int posR = inv[now.mr];
		do{
			auto min(calc(PAIR(now.l, posL - 1)));
			if (min.first == -1) break;
			pq.push(P(now.l, posL - 1, min.first, min.second));
		} while (0);
		do{
			auto min(calc(PAIR(posL+1, posR-1)));
			if (min.first == -1) break;
			pq.push(P(posL + 1, posR - 1, min.first, min.second));
		} while (0);
		do{
			auto min(calc(PAIR(posR + 1, now.r)));
			if (min.first == -1) break;
			pq.push(P(posR + 1, now.r, min.first, min.second));
		}while (0);
	}
	BR;
	return 0;
}

Measured memory_bytes: 9216