#include <bits/stdc++.h>
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
long long s[500009],prefix[500009],n,x,y,first,j,i;
int main()
{
        fin>>n>>first>>x;
    s[1]=x-first;
    for(i=3;i<=n;i++)
    {
        fin>>y;
        s[i-1]=y-x;
        x=y;
    }
    j=1;
    for(i=2;i<n;i++)
    {
        while(j>1&&s[j]!=s[i])
            j=prefix[j-1];
        if(s[j]==s[i])
            j++;
        prefix[i]=j-1;
    }
    j=1;
    while(prefix[j]==0)
        j++;
        fout<<j-1<<'\n';
    for(i=1;i<j;i++)
        fout<<s[i]<<'\n';
}