// editor3
#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)) {
            
        }
        printf("%d\n", num);
        return 0;
    }