/****************************************
* File Name: 1287.cpp
* Author: sky0917
* Created Time: 2014年01月10日 20:16:49
****************************************/
#include <map>
#include <cmath>
#include <queue>
#include <cstdio>
#include <cstring>
#include <algorithm>

#define clr(x) memset(x, 0, sizeof(x))
using namespace std;
const int maxn = 5000003;
          
int tot;
int s, n, sum;

struct node{
    int r, v;
    node *ch[2];

    bool operator < (const node &rhs) const{
        return r < rhs.r;
    }

    int cmp(int x) const{
        if (x == v) return -1;
        return x < v?0:1;
    }

}tt[maxn*2];

void roat(node* &o, int d){
    node *k = o->ch[d^1];
       o->ch[d^1] = k->ch[d];
       k->ch[d] = o;
       o = k;
}

void add(node* &o, int x){
    if (o == NULL){
        o = &tt[tot++];
        o->ch[0] = o->ch[1] = NULL;
        o->v = x;
        o->r = rand();
        sum++;
    }
    else{
        int d = o->cmp(x);
        if (d != -1){
            add(o->ch[d], x);
            if (o->ch[d]->r > o->r)
                roat(o, d^1);
        }
    }
}

void print(node *rt){
    if (rt == NULL)
        return;
    print(rt->ch[0]);
    printf("%d%c",rt->v,++s==sum?‘\n‘:‘ ‘);
    print(rt->ch[1]);
}
int main(){

    while (scanf("%d",&n)!=EOF){
        tot = 0;
        node *root;    
        root = NULL;
        int va;
        sum = 0;
        for (int i=0; i<n; i++){
            scanf("%d",&va);
            add(root, va);    
        }
        s = 0;
        printf("%d\n",sum);
        print(root);
    }    
    return 0;
}