#include<atcoder/all>
using namespace atcoder;

#include <bits/stdc++.h>
template<class T> inline bool chmin(T&a, T b){if(a > b){a = b; return true;}else{return false;}}
template<class T> inline bool chmax(T&a, T b){if(a < b){a = b; return true;}else{return false;}}
#define ll long long
#define double long double
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=1;i<=(n);i++)
#define mod (ll)(1e9+7)
#define inf (ll)(3e18+7)
#define eps (double)(1e-9)
#define pi (double) acos(-1)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;
 
int main() {
    int n;
    cin >> n;
    vector<int> p(n);
    rep(i, n)cin >> p[i];
    rep(i, n)p[i]--;

    vector<int> next(n, -1);
    vector<int> before(n, -1);
    
    rep(i, n-1){
        next[p[i]] = p[i+1];
        before[p[i+1]] = p[i];
    }

    vector<int> ans;
    rep(i, n){
        if(next[i] == -1)continue;
        ans.push_back(i);
        ans.push_back(next[i]);

        if(before[i] != -1)next[before[i]] = next[next[i]];
        before[next[i]] = -1;
        next[next[i]] = -1;
        before[i] = -1;
        next[i] = -1;
    }

    rep(i, n)cout << (i ? " " : "") << ans[i]+1;
    cout << endl;
}