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

int isPalindrome(int num) {
    int original = num, reversed = 0, digit;
    
    while (num > 0) {
        digit = num % 10;
        reversed = reversed * 10 + digit;
        num /= 10;
    }
    
    return original == reversed;
}

int main () {
    int n;
    
    if (scanf("%d", &n) != 1) {
        printf("Invalid input");
        return 0;
    }
    
    if (n < 0) {
        printf("Invalid input");
        return 0;
    }
    
    int next = n + 1;
    while (!ispalindrome(next)) {
        next++;
    }
    
    printf("%d", next);
    
    return 0;
}