#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;
}