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

def chmax(DP,i,v):
    if DP[i] < v: DP[i] = v
def chmin(DP,i,v):
    if DP[i] > v: DP[i] = v

DP = [[-1] * (10) for _ in range(N + 1)]
DP[0][0] = 0

for i in range(N):
    a = A[i]
    for j in range(10):
        if DP[i][j] == -1:
            continue

        # 不採用
        chmax(DP[i + 1], j, DP[i][j])
        # 採用
        chmax(DP[i + 1], (j + a)%10, DP[i][j] + 1)

ans = DP[-1][0]
print(ans)