#include <fstream>
#define nmax (int)(5e5+1)
using namespace std;
ifstream cin("reguli.in");
ofstream cout("reguli.out");
long long a[nmax],n,last,lps[nmax];
void LPS(){
    int i=2,len=0;
    while(i<=n){
        if(a[i]==a[len+1]){
            len++;
            lps[i++]=len;
        }else if(len==0)
            i++;
        else
            len=lps[len-1];
    }
}
int main()
{
    cin>>n>>last;
    for(int i=1;i<n;i++){
        cin>>a[i];
        int aux=a[i]-last;
        last=a[i];
        a[i]=aux;
    }
    n--;
    LPS();
    cout<<n-lps[n]<<'\n';
    for(int i=1;i<=n-lps[n];i++)
        cout<<a[i]<<'\n';
	return 0;
}