// editor3
#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;
}