<?php

$lastSector = readline();
$rowsFirstSector = intval(readline());
$oddSeats = intval(readline());

$n = 0;
$counter = 0;

for ($firstSector = 'A'; $firstSector <= $lastSector; $firstSector++) {
    for ($rows = 1; $rows < $rowsFirstSector + 1; $rows++) {
        if ($rows % 2 == 0) {
            $n = $oddSeats + 2;
        }
        else {
            $n = $oddSeats;
        }

        for ($seats = 97; $seats < $n + 97; $seats++) {
            $counter++;
            echo $firstSector . "" . $rows . "" . chr($seats) . PHP_EOL;
        }
    }
    $rowsFirstSector++;
}

echo $counter;