import strutils, sequtils, math

var a = newSeq[int64](100001)

proc f(i, n: int, b: seq[int64]): bool =
  if i > n: return true
  if i mod 2 == 0:
    a[i] = a[i-1] - b[i-1]
    if a[i] <= 0 or 10^18 < a[i]: return false
    return f(i+1, n, b)
  else:
    a[i] = b[i-1] - a[i-1]
    if a[i] <= 0 or 10^18 < a[i]: return false
    return f(i+1, n, b)

when isMainModule:
  var
    n = stdin.readLine.parseInt
    b = newSeq[int64](n)
    tmp: seq[int64] = @[]

  for i in 0..n-1:
    b[i] = stdin.readLine.parseBiggestInt

  var
    l: int64 = -1
    u = b[0]

  while u - l > 1:
    let m = (u + l) div 2
    a[0] = m
    if f(1, n, b): l = m
    else: u = m

  for i in max(1, l-5)..min(10^18, u+5):
    a[0] = i
    if f(1, n, b):
      echo n+1
      for i in 0..n:
        echo a[i]
      quit()

  echo "-1"