<?php

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

for ($firstSector = 'A'; $firstSector <= $lastSector; $firstSector++) {
    for ($rows = 1; $rows <= $rowsFirstSector; $rows++) {
        for ($seats = 1; $seats <= $oddSeats; $seats++) {
            print $firstSector . "" . $rows . "" . $seats . PHP_EOL;
        }
    }
}