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

# dp[s] = 合計値を10でわったあまりがsのときに選んだカードの最大枚数
INF = 1 << 60
dp = [-INF] * 10
dp[0] = 0
for i in range(N):
    new_dp = dp.copy()
    for s in range(10):
        if dp[s] == -INF:
            continue
        new_dp[(s + A[i]) % 10] = max(new_dp[(s + A[i]) % 10], dp[s] + 1)
    dp = new_dp

print(dp[0])