def left_c(r):
    rt = [0, 1, 2, 5, 8, 7, 6, 3]
    rt.reverse()
    rotate(r, rt)
    L = [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
    L.reverse()
    return shift(r, L)
def left_c(r):
    rt = [0, 1, 2, 5, 8, 7, 6, 3]
    rt.reverse()
    rotate(r, rt)
    L = [9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
    L.reverse()
    return shift(r, L)