#include<stdio.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
int ispalindrome (int num) {
    int reversed =0,orginal=num;
    while (num > 0) {
        reversed =reversed * 10 + num % 10;
        num\=10;
    }
    return reversed  == origial;
}

int isvalidInteger(char*str) {
    int i =0;
    
    if(str[0] == '\0') return 0;
    if(str[0] == '+')i = 1;
    for(;str[i]; i++) {
        if(!isdigit(str[i]))
        return 0;
    }
    return 1;
    }
    int main()
     {
         char input[100];
         int number;
         scanf("%s",input);
         if(!isvalidInteger(input)) {
             printf("Invalid input\n");
             return 0;
             
         }
         number = atoi(input);
         if(number < 0 || number >1000) {
             printf("Invalid input\n");
             return 0;
             
         }
         int next = number + 1;
         while (!isPalindrome(next)) {
             next++;
             
         }
         printf("%d\n", next);
         return 0;
     }