use std::cmp;
use std::io::*;
use std::str::FromStr;

fn calc(n: usize, v: Vec<i32>) -> i32 {
    let mut dp = vec![vec![-1; n + 1]; 10];
    dp[0][0] = 0;

    for i in 0..n {
        for j in 0..10 {
            if dp[j][i] < 0 {
                continue;
            }
            dp[j][i + 1] = cmp::max(dp[j][i + 1], dp[j][i]);
            let val = (v[i] % 10) as usize;
            dp[(j + val) % 10][i + 1] = cmp::max(dp[(j + val) % 10][i + 1], dp[j][i] + 1);
        }
    }

    /*
    for i in 0..10 {
        for j in 0..n + 1 {
            print!("{} ", dp[i][j]);
        }
        println!("");
    }
    */
    dp[0][n]
}

fn main() {
    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    let mut it = s.split_whitespace().map(|x| i32::from_str(x).unwrap());
    let n = it.next().unwrap();

    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    let v: Vec<i32> = s
        .split_whitespace()
        .map(|x| i32::from_str(x).unwrap())
        .collect();

    println!("{}", calc(n as usize, v));
}