import copy
N = int(input()); INF = float("inf")
A = list(map(int,input().split()))

dp = [-INF for _ in range(10)] #dp[i+1][j] i番目まで見て和の1の位がjとなる最大選択可能個数
dp[0] = 0
for i in range(N):
  p = copy.copy(dp)
  p,dp = dp,p
  now = A[i]
  for j in range(10):
    dp[(j+now)%10] = max(dp[(j+now)%10], p[j]+1)
  #print(dp)
#print(dp)
ans = dp[0]
print(ans)