C++ :

#include <cstdlib>
#include <cstdio>
#include <algorithm>
int array[103];
int out[103];
using namespace std;
int main()
{
    int n;
    scanf("%d",&n);
    int n_n=n;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&array[i]);
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            if(array[i]==array[j]&&i!=j)
            {
                n_n--;
                array[i]=-1;
            }
        }
    }
    printf("%d\n",n_n);
    int c=1;
    for(int i=1;i<=n;i++)
    {
        if(array[i]!=-1)
        {
            out[c]=array[i];
            c++;
        }
    }
    sort(out+1,out+n_n+1);
    for(int i=1;i<=n_n;i++)
    {
        printf("%d ",out[i]);
    }
    //system("pause");
    return 0;
}

Pascal :

var n,i,s,x,max:integer; a:array[1..1000] of integer;
begin
  readln(n);
  max:=0;
  for i:=1 to n do
    begin
    read(x);
    inc(a[x]);
    if x>max then max:=x;
    end;
  for i:=1 to max do
    if a[i]<>0 then inc(s);
  writeln(s);
  for i:=1 to max do
    if a[i]<>0 then write(i,' ');
end.