#include <stdio.h>
#include <string.h>
#include <ctype.h>
int isPalindrome(int n) {
    int reversed = 0, original = n;
    while (n > 0) {
        reversed = reversed *10 + (n % 10);
        n /= 10;
    }
    return original == reversed;
}
int isValidNumber(char str[]) {
    int i = 0;
    if (str[0] == '-') return 0;
    while (str[i]) {
        if (!isdigit(str[i]))
        return 0;
        i++;
    }
    return 1;
    int main() {
        char inputstr[100];
        int num;
        scanf("%s", inputstr);
        if (!isValidNumber(inputstr)) {
            printf("Invalid input\n");
            return 0;
        }
        sscanf(inputstr, "%d", &num);
        if (num < -1000 || num > 1000) {
            printf("Invalid input\n");
            return 0;
        }
        num++;
        while (!isPalindrome(num)) {
            num++;
        }
        printf("%d\n", num);
        return 0;
}