import itertools

def read_graph(f):
    """
    Read a nondirected graph from the file given as a parameter.

    The form of the first line of the file is N M K. The vertex set of the 
    graph is V = {0, 1, ..., N - 1}. The next M lines contains U_i V_i pairs
    expressing that U_i V_i is a nondirected edge. K is the number of 
    vertices in a click we are looking for.

    The function returns a triple. The first object is a dictionary of the 
    edges, the second is the number of vertices, the third is the size
    of the click. The dictionary maps every vertex into the 
    list of neighboring vertices. If the list of the vertex U contains 
    the vertex V in its list, then U is in the list of the vertex V, as
    the graph is nondirected.

    :param f: the file containing the graph
    :returns: triple of the dictionary of the edge list, N and K
    """
    head = f.readline().split()
    n, m, k = [int(s) for s in head]

    graph = dict((i, []) for i in range(n))
    for j in range(m):
        edge = f.readline().split()
        u, v = [int(s) for s in edge]
        graph[u].append(v)
        graph[v].append(u)
    return graph, n, k

def main():
    import sys
    with open(sys.argv[1], 'r') as f:
        graph, n, k = read_graph(f)

    # TODO Search for a click of k vertices

if __name__ == '__main__':
    main()