aoc2017-day12

import sys, re, math
from functools import reduce
from functools import partial
from functools import cmp_to_key
from operator import itemgetter
from operator import attrgetter

def rrotate(sequence, amount):
    l = list(sequence)
    amount %= len(l)
    return l[-amount:] + l[:-amount]
def lrotate(sequence, amount):
    l = list(sequence)
    amount %= len(l)
    return l[amount:] + l[:amount]
def slice(sequence, position, length):
    sequence = list(sequence)
    assert(length >= 0 and length <= len(sequence))
    position %= len(sequence)
    return lrotate(sequence,position)[:length]
def insert(sequence, toinsert, position, length=None):
    sequence = list(sequence)
    toinsert = list(toinsert)
    size = length if length != None else len(toinsert)
    assert(size >= 0 and size <= len(sequence))
    position %= len(sequence)
    return rrotate(toinsert[:size] + lrotate(sequence,position)[size:], position)
def xorall(sequence):
    return reduce(lambda x,y: x^y, sequence)
def mulall(sequence):
    return reduce(lambda x,y: x*y, sequence)
def sumall(sequence):
    return reduce(lambda x,y: x+y, sequence)
def splitevery(sequence, step):
    l = list(sequence)
    r = []
    num, rest = divmod(len(l), step)
    for e in range(num):
        r.append(slice(l, e*step, step))
    if rest > 0: r.append(slice(l, num*step, rest))
    return r
def splitin(sequence, number):
    l = list(sequence)
    return splitevery(sequence,(len(l)+number-1)//number)
def formatall(sequence, fmt="%s", sep=""):
    return sep.join(map(lambda x: fmt % x, sequence))
def vecapply(applypair, *sequences):
    return map(applypair, zip(*sequences))
def vecsum(*sequences):
    return list(vecapply(sumall, *sequences))
def vecmul(*sequences):
    return list(vecapply(mulall, *sequences))
def vecxor(*sequences):
    return list(vecapply(xorall, *sequences))
def mandist(*coords):
    return sumall([int(math.fabs(x)) for x in coords])

def parse(input):
    for line in input.split("\n"):
        if line:
            l = re.sub("[-'{}<>,]", "", line).split()
            yield list(l)

#input = open("input12.txt").read()
input = sys.stdin.read()

succs = {}
for l in parse(input):
    all = l
    for s in all:
        if s not in succs: succs[s] = set()
        for n in all:
            succs[s].add(n)
#for i in succs:
#    print(i,succs[i])

def mark(initial, root, succs, group, groups):
    if root in group:
        return
    group[root] = initial
    if initial not in groups: groups[initial] = set()
    groups[initial].add(root)
    for s in succs[root]:
        mark(initial, s, succs, group, groups)

group = {}
groups = {}
for initial in sorted(succs.keys()):
    mark(initial, initial, succs, group, groups)

roots = set()
for i in group:
    roots.add(group[i])
#print(len(roots))
assert(len(roots) == len(groups.keys()))
print(len(groups.keys()))