using static System.Math;
using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, x => int.Parse(x) % 10);
        getAns(n, a);
    }
    static void getAns(int n, int[] a)
    {
        var dp = new int[n, 10];
        for (int i = 0; i < n; i++)
            for (int j = 0; j < 10; j++) dp[i, j] = -1;
        dp[0, a[0]] = 1;
        for (int i = 1; i < n; i++)
        {
            for (int j = 0; j < 10; j++)
            {
                var w = (a[i] + j) % 10;
                if (dp[i - 1, j] != -1) dp[i, w] = Max(dp[i, w], Max(dp[i - 1, w], dp[i - 1, j] + 1));
            }
            for (int j = 0; j < 10; j++)
                if (dp[i, j] == -1) dp[i, j] = dp[i - 1, j];
        }
        Console.WriteLine(Max(0, dp[n - 1, 0]));
    }
}