#include <stdio.h>
#include <string.h>
#include <ctype.h>
int ispalindrpme(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;
        }
        sacnf(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;
    }