#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;
}