import strutils, sequtils, math

var a = newSeq[int64](100010)

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)

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


  var
    d: int64 = max(b[0] div 1000, 1)

  for i in 1..1000:
    var
      l: int64 = d*(i-1)
      u: int64 = d*i

    while u - l > 1:
      let m: int64 = (u + l) div 2
      a[0] = m
      if f(1, n, b): l = m
      else: u = m

    for i in max(1, l-100)..min(b[0]-1, u+100):
      a[0] = i
      if f(1, n, b):
        echo n+1
        for i in 0..n:
          echo a[i]
        quit()

  echo "-1"