#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    a[i] %= 10;
  }
  vector<long long> dp(10 , 0);
  for (int i = 0; i < n; i++) {
    vector<long long> new_dp = dp;
    if (dp[a[i]] == 0) new_dp[a[i]] = 1;
    for (int j = 0; j < 9; j++) {
      if (dp[j] > 0) new_dp[(j + a[i]) % 10] = max(new_dp[(j + a[i]) % 10] , dp[j] + 1);
    }
    dp = new_dp;
  }
  cout << dp[0] << endl;
  return 0;
}