#include <fstream>
using namespace std;
ifstream fin("scmax.in");
ofstream fout("scmax.out");

int n, i, j, v[100010], d[100010], st, dr, mid, indice, k;

int main(){
    fin>>n;
    fin>>v[1];
    k=1;
    d[1]=1;
    for(i=2; i<=n; i++){
        fin>>v[i];
        ///cautam ultimul nr mai mic decat v[i]
        st=1;
        dr=k;
        while(st<=dr){
            mid=(st+dr)/2;
            indice=d[mid];
            if(v[indice]<=v[i]){
                dr=mid-1;
            }else{
                st=mid+1;
            }
        }
        indice=d[dr];
        if(dr==0){
            if(v[k]!=v[i]){
                k++;
                d[k]=i;
            }
        }else{
            d[dr]=i;
        }
    }
    int k2=k;
    for(i=2; i<=k; i++){
        if(v[d[i]]==v[d[i-1]]){
            k2--;
        }
    }
    fout<<k2<<"\n";
    for(i=1; i<=k; i++){
        if(v[d[i]]!=v[d[i-1]]){
            fout<<v[ d[i] ]<<" ";
        }
    }
}