using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var dp = Enumerable.Repeat(int.MinValue, 10).ToArray();
        dp[0] = 0;
        for (var i = 0; i < n; ++i)
        {
            var ndp = (int[]) dp.Clone();
            for (var j = 0; j < n; ++j)
            {
                ndp[(j + a[i]) % 10] = Math.Max(ndp[(j + a[i]) % 10], dp[j] + 1);
            }
            dp = ndp;
        }
        WriteLine(dp[0]);
    }
}