d2_2

#include <iostream>
using namespace std;

bool PalindromCheck(int Num){
    long long int reversedNum = 0;
    int lastDigit;
    while (Num) {
        lastDigit = Num % 10;
        reversedNum = (reversedNum * 10) + lastDigit;
        Num /= 10;
    }
    if (reversedNum == Num)
    {
        return true;
    }
    return false;
}

bool NearestPalindrom(int PalL, int PalR, int Num) {
    if (PalL - Num > Num - PalR)
    {
        return true;
    }
    return false;
}

int main() {
    long long int Num;
    int n_left, n_right;
    cin >> Num;
    if (Num >= 1)
    {
        if (Num < 101)
        {
            cout << "101" << " ";
        }
        else
        {
            if (PalindromCheck(Num) == true)
            {
                cout << Num;
            }
            else
            {
                for (int i = Num;; i++)
                {
                    if (PalindromCheck(i) == true)
                    {
                        n_right = i;
                        break;
                    }
                }
                for (int i = Num ;; i--)
                {
                    n_left = i;
                    break;
                }
                if (NearestPalindrom(n_left, n_right, Num) == false)
                {
                    cout << n_left << " ";
                }
                else
                {
                    cout << n_right << " ";
                }
            }
        }
    }
    else
    {
        cout << "-1" << " ";
    }
}