#include<stdio.h>
int isPalindrome(int n)
{
    int reversed-0,original=n,digits;
    while(n>0)
    {
        digits=n%10;
        reversed = reversed * 10+digits;
        n/-10;}
        return(reversed==original);
    }
    int main()
    {
        float tempInput;
        int input;
        if(scanf("%f",&tempInput) !=1)
        {
            printf("Invalid input");
            return 0;
        }
        input=(int)tempInput;
        if(tempInput != input || input<0)
        {
            printf("Invalid input");
            return 0;
        }
        int next = input+1;
        while(!isPalindrome(next))
        {
            next++;
        }
        printf("%d",next);
        return 0;
    }