N = int(input())
A = list(map(int,input().split()))

dp = [-1] * 10
dp[0] = 0

for a in A:
  new_dp = dp.copy()
  for i in range(10):
    if dp[i] == -1:
      continue
    new_val = (i + a) % 10
    new_dp[new_val] = max(new_dp[new_val], dp[i] + 1)
  dp = new_dp

print(dp[0])