190/2/E

gistfile1.py

n = int(raw_input().strip())

letters = [chr(x) for x in xrange(65, 91)]
cl = 0

graph = [set() for _ in xrange(n)]

for i in xrange(n - 1):
    x, y = map(int, raw_input().strip().split(' '))
    x-=1; y-=1
    graph[x].add(y)
    graph[y].add(x)

ranks = map(len, graph)

def find_centrum(nodes):
    """ Finds girth centrum of the graph and return the central nodes and the subtrees we get by taking out the central node(s). """

    ln = len(nodes)
    cleafs = set([i for i in nodes if len(graph[i]) <= 1])
    needed = ln
    modifiers = {}
    was = set(x for x in cleafs)

    while cleafs:
        if len(cleafs) == needed:
            break
        else:
            nleafs = set()
            for leaf in cleafs:
                maybe_parents = [x for x in graph[leaf] if x not in was]
                if maybe_parents: # for leaf-parent-leaf types
                    parent = maybe_parents[0]
                    if parent in modifiers:
                        modifiers[parent] += 1
                    else:
                        modifiers[parent] = 1
                    if ranks[parent] - modifiers[parent] == 1:
                        nleafs.add(parent)
                        was.add(parent)
            needed -= len(cleafs)
            cleafs = nleafs

    center = cleafs.pop()
    ranks[center] = 0
    tree_starters = [x for x in graph[center]]
    for neighbor in graph[center]:
        graph[neighbor].remove(center)
        ranks[neighbor] -= 1
    graph[center] = set()

    subtrees = [0 for _ in xrange(len(tree_starters))]
    for i, node in enumerate(tree_starters):
        subtree = set([node])
        stack = set([node])
        while stack:
            cnode = stack.pop()
            for neighbor in graph[cnode]:
                if neighbor not in subtree:
                    subtree.add(neighbor)
                    stack.add(neighbor)
        subtrees[i] = subtree

    return (center, subtrees)

forest = [range(n)]
assignments = ["A" for _ in range(n)]

while forest:
    if cl == len(letters):
        print "Impossible!"
        exit()
    nforest = []
    for tree in forest:
        center, subtrees = find_centrum(tree)
        assignments[center] = letters[cl]
        nforest.extend(subtrees)
    cl += 1
    forest = nforest

print " ".join(assignments)