#include <iostream>
#include <vector>
#include <range/v3/all.hpp> // get everything
#include <absl/time/time.h>
#include <absl/time/clock.h>
#include <sstream>
#include <map>
#include <unordered_set>

//using namespace std;
using namespace ::ranges;
using namespace ::ranges::views;

int main() {
    auto start = absl::Now();

    std::unordered_multiset<std::string> lines;
    for (std::string line; std::getline(std::cin, line);) {
        if (line.empty()) break;
        lines.insert(line);
    }

    auto filter_until = [](auto lines, bool keep_most) {
        for (int i = 0; lines.size() > 1; ++i) {
            auto n = count_if(lines, [i](const auto &l) { return l[i] == '1'; });
            bool more_ones = n >= lines.size() - n;
            lines = lines | filter([i, more_ones, keep_most](const std::string &l) {
                return more_ones ^ keep_most ? l[i] == '1' : l[i] == '0';
            });
        }
        return lines;
    };

    auto ox = filter_until(lines, true);
    auto co2 = filter_until(lines, false);

    std::cout << stoi(*ox.begin(), nullptr, 2) * stoi(*co2.begin(), nullptr, 2) << std::endl;
    std::cout << absl::Now() - start << std::endl;
    return 0;
}