#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}
vl calc(vl &v){
  ll n=v.size();
  vl dp(n,INF);
  vl subdp(n);
  rep(i,n){
    ll idx=lower_bound(all(dp),v[i])-dp.begin();
    dp[idx]=v[i];
    subdp[i]=idx;
  }
  ll len=lower_bound(all(dp),INF)-dp.begin();len--;
  vl ans;
  per(i,n){
    if(len==subdp[i]){
      ans.emplace_back(v[i]);
      len--;
    }
  }
  rev(all(ans));
  return ans;
}
int main(){
  ll n;cin >> n;
  vl v(n);rep(i,n)cin >> v[i];
  auto p=calc(v);
  rev(all(v));rep(i,n)v[i]*=-1;
  auto q=calc(v);
  vl ans;
  for(auto val:p){
    if(binary_search(all(q),-val))ans.emplace_back(val);
  }
  cout << ans.size() << endl;
  for(auto p:ans)cout << p <<" ";cout << endl;
}