#include <iostream.h>
#include <fstream.h>
#define MAX 100
void main()
{
	int n,m,good;
	int i,j;
	ofstream out("b.txt");
	char s[MAX];
	cout<<"輸入欲求序列長度:"<<endl;
	cin>>n;
	m=0;
	good=1;
	do{
		if (good)
			if (m==n)
			{
				s[m]='\0';
				out<<s<<endl;
				while(s[m-1]=='3')
					m--;
				s[m-1]++;
			}
			else
				s[m++]='1';
		else
		{
			while (s[m-1]=='3')
				m--;
			s[m-1]++;
		}
		good=1;
		for (j=0;good && j<m/2;j++)
		{
			for (i=0;i<=j;i++)
				if (s[m-2-j-i]!=s[m-1-i])
					break;
			if (i>j)
				good=0;
		}
	}while (m!=0);
	out.close();
}