N = int(input())
A = map(int, input().split())
dp = [-1 for _ in range(10)]
dp[0] = 0
for a in A:
    tmp = [-1 for _ in range(10)]
    for i in range(10):
        if dp[i] == -1:
            continue
        tmp[i] = max(tmp[i], dp[i])
        tmp[(i + a) % 10] = max(tmp[(i + a) % 10], dp[i] + 1)
    dp = tmp
print(dp[0])