#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
int isPalindrome(int n) {
    int original = n;
    int reversed = 0;
    while (n > 0) {
        reversed = reversed * 10 + n % 10;
        n /= 10;
    }
    return original == reversed;
}
int main() {
    char inputstr[20];
    if (scanf("%s", inputstr) != 1) {
        printf("Invalid input\n");
        return 0;
    }
    int isNumeric = 1;
    int hasDecimal = 0;
    for (int i = 0; i < strlen(inputstr); i++) {
        if (!isdigit(inputstr[i])) {
            if (i == 0 && inputstr[i] == '-') continue;
            if (inputstr[i] == '.') hasDecimal = 1;
            else {
                isNumeric = 0;
                break;
            }
        }
    }
    if (!isNumeric || hasDecimal) {
        printf("Invalid input\n");
        return 0;
    }
    long inputNum = atol(inputstr);
    if (inputNum < -1000 || inputNum > 1000) {
        printf("Invalid input\n");
        return 0;
    }
    if (inputNum < 0) {
        printf("Invalid input\n");
        return 0;
    }
    int currentNum = (int)inputNum + 1;
    while (!isPalindrome(currentNum)) {
        curentNum++ ;
    }
    printf("%d\n", currentNum);
    return 0;
}