#include <stdio.h>
#include <string.h>
#include <ctype.h>

// Function to check if a number is palindrome
int isPalindrome(int num) {
    int reversed = 0, original = num;
    while (num > 0) {
        reversed = reversed * 10 + num % 10;
        num /= 10;
    }
    return original == reversed;
}

// Function to validate if input is a valid positive integer
int isValidInput(char str[]) {
    int i = 0;

    // Check if the string is a valid integer number
    while (str[i]) {
        if (!isdigit(str[i]))
            return 0;
        i++;
    }

    // Convert to integer and check if it's in valid range
    int value = atoi(str);
    if (value < 0 || value > 1000)
        return 0;

    return 1;
}

int main() {
    char input[100];
    scanf("%s", input);

    if (!isValidInput(input)) {
        printf("Invalid input\n");
        return 0;
    }

    int num = atoi(input);
    num++; // Start checking from next number

    while (1) {
        if (isPalindrome(num)) {
            printf("%d\n", num);
            break;
        }
        num++;
    }

    return 0;
}