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

dp = [float("-inf")] * 10
dp[0] = 0

for i in range(N):

    ndp = [float("-inf")] * 10

    for j in range(10):

        ndp[j] = max(ndp[j] , dp[j])
        ndp[(A[i] + j) % 10] = max( ndp[(A[i] + j) % 10] , dp[j] + 1)

    dp = ndp
    
print (dp[0])