N = int(input())
A = list(map(int,input().split()))
INF = 10**15
dp = [[-INF for _ in range(10)] for _ in range(N+1)]
dp[0][0] = 0
for i in range(1,N+1):
    for j in range(10):
        dp[i][j] = max(dp[i-1][j],dp[i-1][(j-A[i-1])%10]+1)
print(dp[N][0])