import std.stdio;
import std.datetime;
import std.file;
import std.format;
import std.algorithm;
import std.string;
import std.range;

void main(string[] args)
{
    auto logLines = readText("data.txt").splitLines().sort();
    int year, month, day, hour, min, g, startMinute;
    int[][int] guards;
    string log;

    foreach(line; logLines) {
        line.formattedRead!"[%d-%d-%d %d:%d] %s"(year, month, day, hour, min, log);
        auto date = DateTime(year, month, day, hour, min);

        final switch(log[0]) {
            case 'G':
                log.formattedRead!"Guard #%d begins shift"(g);
                break;

            case 'f':
                startMinute = date.minute;
                break;

            case 'w':
                guards[g] ~= iota(startMinute, date.minute, 1).array;
                break;
        }
    }

    auto minuteSum = guards.values.map!(a => a.length);
    auto id = assocArray(zip(minuteSum, guards.keys))[minuteSum.maxElement];
    auto minutesCount = guards[id].sort.group.assocArray;
    auto maxCount = minutesCount.values.reduce!max;
    auto minute = assocArray(zip(minutesCount.values, minutesCount.keys))[maxCount];

    writeln(id * minute);
}