#include <iostream>
#include <fstream>
using namespace std;
ifstream f("reguli.in");
ofstream g("reguli.out");

long long i,j,n,k,a[500010];
int c[500010],d[500010];

int main()
{
f>>n;
for (i=1;i<=n;i++)
{
    f>>a[i];
}
n--;
for (i=1;i<=n;i++)
{
    a[i]=a[i+1]-a[i];

}
j=0;
for (i=2;i<=n;i++)
{
    while (a[j+1]!=a[i] && j) j=c[j];
    if (a[i]==a[j+1]) {c[i]=j+1;j++;}
}
g<<n-c[n]<<"\n";
for (i=1;i<=n-c[n];i++)
    g<<a[i]<<"\n";


    return 0;
}