#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, v;
  int sum = 0;
  int cnt[10];
  memset(cnt, 0, sizeof cnt);
  cin >> n;
  while (n--) {
    cin >> v;
    cnt[v]++;
    sum += v;
  }
  if (cnt[0] == 0) {
    cout << "-1";
    return 0;
  }
  int mod = sum % 3;
  if (mod != 0) {
    bool deleted = 0;
    for (int i = mod; i < 9; i += 3) {
      if (cnt[i] > 0) {
        deleted = 1;
        cnt[i]--;
        break;
      }
    }
    if (!deleted) {
      int left = 2;
      for (int i = mod == 1 ? 2 : 1; i < 9 && left; i += 3) {
        int take = min(left, cnt[i]);
        left -= take;
        cnt[i] -= take;
      }
    }
  }
  string res;
  for (int i = 9; i >= 0; i--) {
    if (i == 0 && res.empty()) cnt[0] = 1;
    res += string(cnt[i], '0' + i);
  }
  cout << res;
}
