wedding_seats

last_sector = input()
list_alphabet_up = []
list_alphabet_lo_odd = []
list_alphabet_lo_even = []
count_rows_first_sector = int(input())
count_seats_odd_row = int(input())
end_lett_odd_row_seats = 97 + count_seats_odd_row


n = ord(last_sector)
# print(n)
res = ""
for indx in range(65, 91):   # 65 - 90 Cap, Буква = chr(idx), ASCII = ord(char)
    if indx <= n:
        list_alphabet_up.append(chr(indx))
for indx in range(97, 123):   # 97 - 122 lower, Буква = chr(idx), ASCII = ord(char)
    if indx < end_lett_odd_row_seats:
        list_alphabet_lo_odd.append(chr(indx))
for indx in range(97, 123):   # 97 - 122 lower, Буква = chr(idx), ASCII = ord(char)
    if indx < end_lett_odd_row_seats + 2:   # Места на четните редове
        list_alphabet_lo_even.append(chr(indx))
add_row = 0
all_seats = 0
# print(list_alphabet_up)
# print(list_alphabet_lo)
for sect in list_alphabet_up:
    for row in range(1 , count_rows_first_sector + add_row + 1):
        if row % 2:
            for seat in list_alphabet_lo_odd:
                print(sect + str(row) + seat)
                all_seats += 1
        elif not row % 2:
            for seat in list_alphabet_lo_even:
                print(sect + str(row) + seat)
                all_seats += 1
    add_row += 1
print(all_seats)

# print(f'{сектор}{ред}{място}')