# a2 = b1 - a1
# a3 = a2 - b2 = - b2 + b1 - a1
# a4 = b3 - a3 = b3 + b2 - b1 + a1
# a5 = a4 - b4 = -b4 + b3 + b2 - b1 + a1
# a6 = b5 - a5

import sys
input = sys.stdin.readline

N = int(input())
ans = [0] * N
v = 0
now = 0
for i in range(N):
    b = int(input())
    if i % 2:
        now = now - b
    else:
        now = b - now
    ans[i] = now
    if 2 <= i % 4 <= 3:
        v = min(v, now - 1)

a = max(1, -v)
for i in range(N):
    if i % 4 <= 1:
        ans[i] -= a
    else:
        ans[i] += a
    if ans[i] <= 0:
        print(-1)
        exit()

print(N + 1)
print(a)
for a in ans:
    print(a)