from copy import deepcopy


def makeAdj(arr, n):
    adj = [[] for i in range(n)]
    for i in arr:
        adj[i[0]].append(i[1])
        adj[i[1]].append(i[0])
    return [sorted(i) for i in adj]


def checkConnectedness(adj):
    used = [False for i in range(len(adj))]
    used[0] = True
    stackDfs = [0]

    while stackDfs:
        point = stackDfs.pop()
        for v in adj[point]:
            if not used[v]:
                stackDfs.append(v)
                used[v] = True
    if False in used:
        return False
    return True


def getJunctionPoints(adj):
    junctionPoints = []
    used = [False for i in range(len(adj))]
    while False in used:
        tempAdj = deepcopy(adj)
        v = 0
        for i in range(len(used)):
            if not used[i]:
                used[i] = True
                v = i
                break
        tempAdj[v] = []
        for i in range(len(tempAdj)):
            for j in range(len(tempAdj[i])):
                if tempAdj[i][j] == v:
                    tempAdj[i].pop(j)
                    break

        removeElem = 0
        for i in range(len(tempAdj)):
            if not tempAdj[i]:
                removeElem = i
                break
        tempAdj.pop(removeElem)
        for i in range(len(tempAdj)):
            for j in range(len(tempAdj[i])):
                if tempAdj[i][j] > removeElem:
                    tempAdj[i][j] -= 1

        if not checkConnectedness(tempAdj):
            junctionPoints.append(v)
    return junctionPoints


def getComponents(adj):
    junctionPoints = getJunctionPoints(adj)
    if not junctionPoints:
        return []

    used = [False for i in range(len(adj))]
    for i in junctionPoints:
        used[i] = True

    stackDfs = [junctionPoints[0]]
    component = []
    while "Python is cool":
        if not stackDfs:
            yield component
            if False not in used:
                return
            component = []
            for i in range(len(used)):
                if not used[i]:
                    stackDfs.append(i)
                    used[i] = True

        point = stackDfs.pop()
        component.append(point)
        for v in adj[point]:
            if not used[v]:
                stackDfs.append(v)
                used[v] = True


if __name__ == "__main__":
    n = 7
    arr = [(0, 1), (0, 3), (1, 3), (2, 3), (3, 4), (4, 5), (4, 6), (5, 6)]
    adj = makeAdj(arr, n)
    for i in getComponents(adj):
        print(i)