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