#include <fstream>

using namespace std;

long long a[100000];
unsigned long n;
void p(unsigned long i)
{
    unsigned long j,l;
    for(j=i+1;j<=n;j++)
    {
        if(a[i]==a[j])
        {
            for(l=j+1;l<=n;l++)
            {
                a[j]=a[l];
            }
            n--;
        }
    }
}
void sortare()
{
    unsigned long j,l;
    long long aux;
    for(j=1;j<=n;j++)
        for(l=j+1;l<=n;l++)
        {
            if(a[l]<a[j])
            {
                aux=a[l];
                a[l]=a[j];
                a[j]=aux;
            }
        }
}
int main()
{
    unsigned long i;
    ifstream f("scmax.in");
    ofstream g("scmax.out");
    f>>n;
    for(i=1;i<=n;i++)
        f>>a[i];
    for(i=1;i<=n;i++)
        p(i);
    for(i=1;i<=n;i++)
        sortare();
    g<<n<<endl;
    for(i=1;i<=n;i++)
        g<<a[i]<<" ";
    return 0;
}