/* -*- coding: utf-8 -*-
 *
 * 1231.cc:  No.1231 Make a Multiple of Ten - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

/* global variables */

int dp[MAX_N + 1][10];

/* subroutines */

inline void setmax(int &a, int b) { if (a < b) a = b; }

/* main */

int main() {
  int n;
  scanf("%d", &n);

  memset(dp, -1, sizeof(dp));
  dp[0][0] = 0;

  for (int i = 0; i < n; i++) {
    int ai;
    scanf("%d", &ai);

    for (int j = 0; j < 10; j++)
      if (dp[i][j] >= 0) {
	setmax(dp[i + 1][j], dp[i][j]);
	setmax(dp[i + 1][(j + ai) % 10], dp[i][j] + 1);
      }
  }

  printf("%d\n", dp[n][0]);
  return 0;
}