import java.io.BufferedReader
import java.io.InputStream
import java.io.InputStreamReader
import java.io.PrintWriter
import java.util.*

fun PrintWriter.solve(sc: FastScanner) {
    val n = sc.nextInt()
    val a = Array(n) { sc.nextInt() }
    val dp = Array(n + 1) { Array(10) { -1 } }
    dp[0][0] = 0
    for (i in 0 until n) {
        for (j in 0 until 10) {
            val k = (a[i] + j) % 10
            if (dp[i][j] != -1) {
                dp[i + 1][k] = maxOf(dp[i][k], dp[i][j] + 1)
            } else {
                dp[i + 1][k] = dp[i][k]
            }
        }
    }
    println(dp[n][0])
}

fun main() {
    val writer = PrintWriter(System.out, false)
    writer.solve(FastScanner(System.`in`))
    writer.flush()
}

class FastScanner(s: InputStream) {
    private var st = StringTokenizer("")
    private val br = BufferedReader(InputStreamReader(s))

    fun next(): String {
        while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine())

        return st.nextToken()
    }

    fun nextInt() = next().toInt()
    fun nextLong() = next().toLong()
    fun nextLine() = br.readLine()
    fun nextDouble() = next().toDouble()
    fun ready() = br.ready()
}