//
// Created by Matthew Gretton-Dann on 02/12/2021.
//

#include <string>
#include <iostream>

int main()
{
    using namespace std::string_literals;

    static const auto fwd{"forward "s};
    static const auto down{"down "s};
    static const auto up{"up "s};

    std::string line;
    unsigned long horiz{0};
    unsigned long depth{0};
    unsigned long aim{0};
    while (std::getline(std::cin, line)) {
        if (line.size() > fwd.size() && line.substr(0,fwd.size()) == fwd) {
            auto dist{std::stoul(line.substr(fwd.size()))};
            horiz += dist;
            depth += aim * dist;
        }
        if (line.size() > down.size() && line.substr(0,down.size()) == down) {
            aim += std::stoul(line.substr(down.size()));
        }
        if (line.size() > up.size() && line.substr(0,up.size()) == up) {
            aim -= std::stoul(line.substr(up.size()));
        }
    }

    std::cout << "Distance * depth: " << horiz << " * " << depth << " = " << horiz * depth << '\n';
}