Envío 718

Código

n_arr = int(input())
arr = map(int, input().split(' '))

sums = [0]*(n_arr+1)
positive_idxs = []
for n, p in enumerate(arr):
  psum = sums[n] + p
  sums[n+1] = psum
  # Narrow down to possible solutions for the left side
  if psum > 0:
    positive_idxs.append(n)

if len(positive_idxs) > 0:
  S = sums[-1]  # total sum
  for s_gt_zero_idx in positive_idxs:
    s_complement = S - sums[s_gt_zero_idx]
    if s_complement < 0:
      print(s_gt_zero_idx)
      break
  else:
    print('Impossible')
else:
  print('Impossible')