#include  <iostream>
using namespace std;
int main()
{
  int n; cin >> n;int a[n],b[n],i,count=0;
  for (i=0;i<n;i++)
      cin >> a[i];b[0]=a[0];
    for (i=1;i<n;i++)
    {
        if (a[i]==a[i-1]) { count ++ ;b[i]=INT_MIN; } else b[i]=a[i];
    }
    cout << count << endl;
    for(i=0;i<n;i++)
        if (b[i]!=INT_MIN) cout << b[i] << " ";
}