#include <cstdio>

using namespace std;
long long int v[500005];
int main()
{
    freopen("reguli.in","r",stdin);
    freopen("reguli.out","w",stdout);
    int n,i,m,con;
    long long int last,x;
    scanf ("%d",&n);
    last=0;
    for (i=0;i<n;i++)
    {
        scanf ("%lld",&x);
        if (i==0)
        {
            last=x;
        }
        else
        {
            v[i]=x-last;
            last=x;
        }
    }
    con=1;
    v[n]=v[1];
    while(v[con+2]!=v[1])
    {
        con++;
    }
    m=con;
    for(i=con+2;i<=n-1;i++)

    {
        if(v[i]!=v[i-con])
        {
            m++;
            con++;
        }
    }

    for(i=1;i<n-m;i++)
    {
        if(v[i]!=v[i+m])
            m=n-1;
    }
    printf("%d\n",m);
    for(i=1;i<=m;i++)

    {
        printf("%d\n",v[i]);
    }
    return 0;
}