#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<list<int>::iterator> its(n);
  list<int> p;
  rep(i, n) {
    int pi;
    cin >> pi;
    pi--;
    p.emplace_back(pi);
    its[pi] = prev(p.end());
  }
  vector<char> used(n);
  VI q;
  rep(v, n) if (!used[v]) {
    auto it = its[v];
    auto nit = next(it);
    if (nit == p.end()) continue;
    q.emplace_back(*it);
    q.emplace_back(*nit);
    used[*it] = used[*nit] = true;
    p.erase(it);
    p.erase(nit);
  }
  assert(ssize(q) == n);
  rep(i, n) cout << q[i] + 1 << " \n"[i + 1 == n];
}