n=int(input())
arr=list(map(int,input().split()))
arr=[arr[i]%10 for i in range(n)]
dp=[[0]*10 for _ in range(n+1)]
for i in range(1,n+1):
    val=arr[i-1]
    for j in range(10):
        dp[i][j]=max(dp[i][j],dp[i-1][j])
        if dp[i-1][j]!=0:
            dp[i][(j+val)%10]=max(dp[i][(j+val)%10],dp[i-1][j]+1)
    dp[i][val]=max(dp[i][val],1)
print(max(1,dp[n][0]))