#include<stdio.h>
#include<string.h>
#include<ctype.h>
int is Palindrome(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("Invali input");
        return 0;
    }
    sscanf(inputStr, "%d", &num);
    if(num < -1000 || num >1000){
        printf("Invalid input");
        return 0;
    }
    num++;
    while(!isPalindrome(num)){
        num++;
    }
    printf("%d", num);
    return 0;
}