#include <cstdio>
using namespace std;
long long a[500020];
int pi[500020];
long long n,m;
void R()
{
    freopen("reguli.in","r",stdin);
    scanf("%d",&n);
    long long p,x,i;
    scanf("%d",&x);
    for(i=1; i<n; i++)
    {
        p=x;
        scanf("%d",&x);
        a[i]=x-p;
    }
    n--;

}

void Prefix()
{
    long long i,k=0;
    pi[1]=0;
    for(i=2; i<=n; i++)
    {
        while(k>0 && a[k+1]!=a[i])
            k=pi[k];
        if(a[k+1]==a[i])
            k++;
        pi[i]=k;
    }

    m=n-pi[n];
}
int main()
{
    R();
    Prefix();
    freopen("reguli.out","w",stdout);
    printf("%d\n",m);
    for(int i=1; i<=m; i++)
        printf("%lld\n",a[i]);
    return 0;
}