import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int[][] dp = new int[n + 1][10];
        Arrays.fill(dp[0], Integer.MIN_VALUE);
        dp[0][0] = 0;
        for (int i = 1; i <= n; i++) {
            int x = sc.nextInt() % 10;
            for (int j = 0; j < 10; j++) {
                dp[i][j] = Math.max(dp[i - 1][j], dp[i - 1][(j + 10 - x) % 10] + 1);
            }
        }
        System.out.println(dp[n][0]);
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}