using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp3 {
    class Program {
        static void Main(string[] args) {
            var scanner = new Scanner();
            int N = scanner.NextInt();
            int[] A = new int[N];
            for (int i = 0; i < N; i++) {
                A[i] = scanner.NextInt();
            }
            int[] dp = new int[10];
            for (int i = 0; i < 10; i++) {
                dp[i] = int.MinValue;
            }
            dp[0] = 0;
            foreach (int x in A) {
                int[] to = new int[10];
                for (int i = 0; i < 10; i++) {
                    to[i] = dp[i];
                }
                for (int i = 0; i < 10; i++) {
                    to[(i + x) % 10] = Math.Max(to[(i + x) % 10], dp[i] + 1);
                }
                dp = to;
            }
            Console.WriteLine(dp[0]);
        }
    }

    class Scanner {
        int index = 0;
        string[] tokens = { };

        public string Next() {
            if (index == tokens.Length) {
                index = 0;
                tokens = Console.ReadLine().Split(' ');
            }
            return tokens[index++];
        }

        public int NextInt() {
            return int.Parse(Next());
        }

        public long NextLong() {
            return long.Parse(Next());
        }

        public double NextDouble() {
            return double.Parse(Next());
        }
    }
}