#include<stdio.h>
 #include<string.h>
 #include<ctype.h>
 int ispalindrome(int n) {
     int reversed = 0, original = n;
     while (n > 0) {
         reversed = resversed * 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];
    intt 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)) {
        num++;
    }
    printf("%d\n", num);
    return 0;
}