n = int(input())
weights = list(map(int, input().split()))

dp = [[False] * 10001 for _ in range(n+1)]
weight_sum = sum(weights)
if weight_sum & 1:
  print("impossible")
  exit()

dp[0][0] = True

for i in range(n):
  for j in range(10001):
    if dp[i][j]:
      dp[i + 1][j + weights[i]] = True
      dp[i + 1][j] = True

if dp[n][weight_sum // 2]:
  print("possible")
else:
  print("impossible")