#include <stdio.h>
#include <stdbool.h>
bool isPalindromic(int n)
{
    int rev = 0, orig = n;
    while (n > 0) {
        rev = rev * 10 + n % 10;
        n /= 10;
    }
    return rev == orig;
}

int p4()
{
    int max = 0;
    for (int i = 100; i <= 999; i++) {
        for (int j = i; j <= 999; j++) {
            int prod = i * j;
            if (prod > max && isPalindromic(prod))
                max = prod;
        }
    }
    printf("%d\n", max);
    return 0;
}