#include <stdio.h>
#include <stdlib.h>
 
void next_palin(char*str_of_num,int* lenth_p);/*产生下一个回文数*/
 
int main()
{
    int num,lenth=1;
    int i,count=1;
    char str_of_num[30]="1";
 
    while (scanf("%d",&num)!=EOF)
    {
        while (count<num)
        {
            next_palin(str_of_num,&lenth);
            count++;
        }
 
        for (i=0;i<lenth;i++)
            putchar(str_of_num[i]);
        putchar(’\n’);
    }
 
    return 0;
}
 
void next_palin(char*str_of_num,int* lenth_p)/*产生下一个回文数*/
{
    int i;
    int flag=1;
 
    for (i=0;i<*lenth_p;i++)
    {
        if (str_of_num[i]!=’9′)
        {
            flag=0;
        }
    }
 
    if (flag)
    {
        (*lenth_p)++;
        str_of_num[0]=str_of_num[*lenth_p-1]=’1′;
 
        for (i=1;i<*lenth_p-1;i++)
        {
            str_of_num[i]=’0′;
        }
    }
    else
    {
        i=*lenth_p/2;
        str_of_num[i]++;
        str_of_num[*lenth_p-1-i]=str_of_num[i];
        while ((str_of_num[i]>’9′) && (i<*lenth_p-1))
        {
            str_of_num[i]=str_of_num[*lenth_p-i-1]=’0′;
            str_of_num[i+1]++;
            str_of_num[*lenth_p-i-2]++;
            i++;
        }
    }
}