#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 25;
const long long LL_INF = 1ll << 61;
int main() {
  int n;
  scanf("%d", &n);
  vector<int> count(3, 0);
  for (int i = 0; i < n; i++) {
    int num;
    scanf("%d", &num);
    count[num]++;
  }
  if (count[1] == 0) {
    for (int i = 0; i < count[2]; i++) printf("2 ");
    printf("\n");
  } else {
    if (count[2] == 0) {
      for (int i = 0; i < count[1]; i++) printf("1 ");
      printf("\n");
    } else {
      printf("2 1 ");
      count[2]--;
      count[1]--;
      for (int i = 0; i < count[2]; i++) printf("2 ");
      for (int i = 0; i < count[1]; i++) printf("1 ");
      printf("\n");
    }
  }
  return 0;
}
