#!/usr/bin/python
import sys, os, string

Debug=0

def debug(*args):
    global Debug
    if Debug > 0:
        print args

def readGraph(filename, nodes):
    digraph = {}
    f = open(filename, "r")
    if f == False:
        exit(-1)  
    debug(f)
    for line in f:
        line = line.rstrip('\n')
        if len(line) == 0:
            continue
        parts = line.split('\t')
        debug("parts", parts)
        # assert len(parts) == 3
        src = parts[1]
        dst = parts[2]
        debug("src=", src, "dst=", dst)
        digraph[src + "," + dst] = 1
        dictIncr(nodes, src)
        dictIncr(nodes, dst)
    # endwhile
    f.close()
    return digraph

def dictIncr(a, k):
    if k in a:
        a[k] += 1
    else:
        a[k] = 1


def buildcluster(digraph, clusters, nodes):
    for n in nodes:
        debug("check node", n)
        added = False
        for cn in clusters.keys():
            debug("  checking cluster", cn)
            if highlyConnected(digraph, clusters[cn], n):
                debug("  adding", n, "to", cn)
                clusters[cn].append(n)
                added = True
                # break
            # if
        # for cn
        if not added:
            debug("  * new cluster for", n)
            clusters[n] = [n]
        # if
    # for
    return len(clusters)


def highlyConnected(digraph, cnodes, node):
    for cn in cnodes:
        if not isHighlyConnected(cn, node, digraph):
            return False
    return True

def isHighlyConnected(a, b, g):
    if (a + "," + b) in g \
            and (b + "," + a) in g:
        return True
    else:
        return False

def emitClusters(c):
    nc = {}
    for k, nl in c.items():
        if len(nl) < 3:
            continue
        nl.sort()
        nk = ", ".join(nl)
        nc[nk] = 1
    nck = sorted(nc.keys())
    for k in nck:
        print k

def main():
    fn = sys.argv[1]
    debug("file=" + fn)
    nodes = {}  # hash(node) -> count
    digraph = readGraph(fn, nodes)
    debug("digraph=", digraph)
    debug("nodes=", nodes)
    clusters = {}  # hash(node) -> [n, ...]
    buildcluster(digraph, clusters, nodes)
    debug("clusters=", clusters)
    emitClusters(clusters)

if __name__ == '__main__':    
    main()