#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");
int n;
int a[500010],b[500010];
int helper[500010];
void build()
{
    for(int i = 1,j=0;i<n;i++)
    {
        while(j && b[i]!=b[j])
            j = helper[j-1];
        if(b[j]==b[i])
            j++;
        helper[i]=j;
    }
}
int main()
{
    fin>>n;
    fin>>a[0];
    for(int i = 1;i<n;i++)
    {
        fin>>a[i];
        b[i-1]=a[i]-a[i-1];
    }
    n--;
    build();
    int sol;
    sol = n-1-helper[n-1];
    fout<<sol+1<<'\n';
    for(int i = 0;i<=sol;i++)
        fout<<b[i]<<'\n';
    return 0;
}