# coding: utf-8
# Your code here!
N=int(input())
A=list(map(int,input().split()))

dp=[-1]*10
dp[0]=0

for a in A:
    temp=dp[:]
    for i in range(10):
        if dp[i]!=-1:
            temp[(a+i)%10]=max(dp[i]+1,temp[(a+i)%10])
    dp=temp[:]

print(dp[0])