#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef long double ld;
typedef pair<int,int> P;
constexpr int INF = 1e9;
int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i,n) cin >> a[i];
  vector<int> dp(10, -1);
  dp[0] = 0;
  for (int i = 0; i < n; i++) {
    auto ndp = dp;
    for (int j = 0; j < 10; j++) {
      if (dp[j] == -1) continue;
      ndp[(j + a[i]) % 10] = max(dp[(j + a[i]) % 10], dp[j] + 1);
    }
    dp = move(ndp);
  }
  cout << dp[0] << endl;
  return 0; 
}