def step1(k):
      return  {
              'A': "G".split(','),
              #B
              'B': "J,L,G".split(','),
              #C
              'C': "E,K,M,H".split(','),
              #D
              'D': "L".split(','),
              #E
              'E': "P,L,C".split(','),
              #F
              'F': "J,P,Q".split(','),
              #G
              'G': "A,B,K,R,N".split(','),
              #H
              'H': "C,L,Q".split(','),
              #I
              'I': "P".split(','),
              #J
              'J': "S,F,B".split(','),
              #K
              'K': "T,Q,G,C".split(','),
              #L
              'L': "B,E,O,S,U,R,H,D".split(','),
              #M
              'M': "C,P,T".split(','),
              #N
              'N': "G,Q".split(','),
              #O
              'O': "T,L".split(','),
              #P
              'P': "E,I,V,U,M,F".split(','),
              #Q
              'Q': "F,K,S,V,N,H".split(','),
              #R
              'R': "G,L,T".split(','),
              #S
              'S': "J,Q,L".split(','),
              #T
              'T': "K,O,R,M".split(','),
              #U
              'U': "L,P".split(','),
              #V
              'V': "P,Q".split(',')
       }.get(k,'')
def step2(k):
       return {
              # A
              'A': "B,D".split(','),
              # B
              'B': "E,F,A".split(','),
              # C
              'C': "G".split(',') , #Like step1('A')
              # D
              'D': "A,F,H".split(','),
              # E
              'E': "I,K,B".split(','),
              # F
              'F': "B,K,M,D".split(','),
              # G
              'G': "C,L".split(','), #step2('G') == step1('H')-'Q'
              # H
              'H': "D,M,N".split(','),
              # I
              'I': "O,E".split(','),
              # J
              'J': "P".split(','), #like step1('I')
              # K
              'K': "E,O,F".split(','),
              # L
              'L': "PQG",
              # M
              'M': "FRH",
              # N
              'N': "HR",
              # O
              'O': "ISK",
              # P
              'P': "JTL",
              # Q
              'Q': "LT",
              # R
              'R': "MUN",
              # S
              'S': "OV",
              # T
              'T': "PQ", #like step1('V')
              # U
              'U': "VR",
              # V
              'V': "SU",
       }.get(k,'')