N = int(input())
A = list(map(int, input().split()))
dp = [-1] * 10
dp[0] = 0
for a in A:
    dp2 = [-1] * 10
    for i in range(10):
        if dp[i] > -1:
            dp2[(i + a) % 10] = dp[i] + 1
    for i in range(10):
        dp[i] = max(dp[i], dp2[i])
print(dp[0])