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

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

int isValidInteger(char str[]) {
    for (int i = 0; str[i] != '\0'; i++) {
        if (!isdigit(str[i])) {
            return 0;
        }
    }
    return 1;
}
int main() {
    char input[100];
    scanf("%s", input);
    
    if (!isValidInteger(input)) {
        printf("Invalid Input\n");
        return 0;
    }
    
    long long num = atoi(input);
    
    if (num < 0) {
        printf("Invalid Input\n");
        return 0;
    }
    
    num++;
    while (!ispalindrome(num)) {
        num++;
    }
    
    printf("%lld\n", num);
    return 0;
}