// editor3
#include <stdio.h>

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

int main() {
    int n;
    
    if (scanf("%d", &n) != 1) {
        printf("Invalid input");
        return 0;
    }
    
    if (n < 0) {
        printf("Invalid input");
        return 0;
    }
    
    int next = n + 1;
    
    while (1) {
        if (isPalindrome(next)) {
            printf("%d", next);
            break;
        }
        next++;
    }
    
    return 0;
}