#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;
    }
    intput=(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;
}