#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr ll LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n; cin >> n;
  vector<int> a(10, 0);
  while (n--) {
    int ai; cin >> ai;
    ++a[ai % 10];
  }
  int ans = 0;
  REP(i, 10) {
    ans += a[i] / 10;
    a[i] %= 10;
  }
  vector dp(11, vector(10, -INF));
  dp[0][0] = 0;
  REP(i, 10) REP(j, 10) REP(k, a[i] + 1) chmax(dp[i + 1][(j + k * i) % 10], dp[i][j] + k);
  cout << ans + dp[10][0] << '\n';
  return 0;
}