n = int(input())
a = list(map(int, input().split()))
dp = [-10**9] * 10
dp[0] = 0
for x in a:
    dp_new = [0] * 10
    for i in range(10):
        dp_new[(i + x) % 10] = max(dp[(i + x) % 10], dp[i] + 1)
    dp = dp_new
print(dp[0])