import sys
from collections import defaultdict

wardrobes = []
current = []

for line in sys.stdin:
    line = line.strip()
    if line == "@":
        wardrobes.append(current)
        current = []
    elif line == "#":
        wardrobes.append(current)
        break
    else:
        current.append(line)
total = 1
for w in wardrobes:
    total *= len(set(w))
color_count = defaultdict(int)
for w in wardrobes:
    for c in w:
        color_count[c] += 1

if color_count:
    max_freq = max(color_count.values())
    most = sorted(c for c, v in color_count.items() if v == max_freq)
else:
    most = []
n = len(wardrobes)
perfect = []
for c in color_count:
    count = 0
    for w in wardrobes:
        if c in w:
            count += 1
    if count == n:
        perfect.append(c)

perfect = sorted(perfect)

print(total)
print(",".join(most))
print(",".join(perfect))