import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();
        int[] a=new int[n];
        for (int i=0;i<a.length;i++){
            a[i]=in.nextInt();
        }
        moveZeroes(a);
        for (int i=0;i<a.length;i++){
            System.out.print(a[i]);
        }

    }
        public static void moveZeroes(int[] nums) {
            for (int i=0;i<nums.length-1;i++){
                for (int j=i+1;j<nums.length;j++){
                    if (nums[i]==0&&nums[j]!=0){
                        int temp=nums[i];
                        nums[i]=nums[j];
                        nums[j]=temp;
                        break;
                    }

                }
            }
        }
    }