#include <bits/stdc++.h>
#define L 500005
using namespace std;
ifstream fin("reguli.in");
ofstream fout("reguli.out");

int n;
long long v[L], s[L];
int z[L];

void Z(){
  z[0] = 0;
  int r = 1, l = 0;
  for (int i = 1; i < n; i++){
    z[i] = min(r - i, z[i - l]);
    while (i + z[i] < n && s[z[i]] == s[i + z[i]])
      z[i]++;
    if (i + z[i] >= r){
      r = max(i + 1, i + z[i]);
      l = i;
    }
  }
}

int main(){
  fin >> n;
  for (int i = 0; i < n; i++)
    fin >> v[i];
  for (int i = 0; i < n - 1; i++)
    s[i] = v[i + 1] - v[i];
  n--;
  Z();
  int ans = n;
  for (int i = 1; i <= n; i++)
    if (i + z[i] == n){
      ans = i;
      i = n;
    }
  fout << ans << "\n";
  for (int i = 0; i < ans; i++)
    fout << s[i] << "\n";
  return 0;
}