/*
 project euler problem 4: 找出由两个三位数相乘的最大的回文数。
 answer: 906609
*/
#include<bits/stdc++.h>
using namespace std;

bool check(int num)
{
    string s = to_string(num);
    string t = s;
    reverse(t.begin(), t.end());

    return s == t;
}

int main(void)
{
    int ans = 0;
    for (int i = 100; i < 1000; ++i)
        for (int j = 100; j < 1000; ++j)
            if (check(i * j)) ans = max(ans, i * j);

    cout << ans << endl;
}