A = [0b11000000, 0b11000000]
B = [0b10000000, 0b10000000, 0b10000000, 0b10000000]
C = [0b11110000]
D = [0b01000000, 0b11000000, 0b10000000]
E = [0b11000000, 0b01100000]
F = [0b10000000, 0b11000000, 0b01000000]
G = [0b011000000, 0b11000000]

def matchable(source, target, width)
  return false  if source.length != target.length
  
  (9 - width).times{|n|
    found = true
    source.length.times{|l|
      found = false   if source[l] ^ target[l] >> n != 0
    }
    return true  if found
  }
  return false
end

def cutFigure(figure)
  subFigure = Array.new
  figure.each{|n|
    subFigure << n  if n != 0
  }
  return subFigure
end

def findFigure(figure)
  source = cutFigure(figure)
  return "A"  if matchable(source, A, 2)
  return "B"  if matchable(source, B, 1)
  return "C"  if matchable(source, C, 4)
  return "D"  if matchable(source, D, 2)
  return "E"  if matchable(source, E, 3)
  return "F"  if matchable(source, F, 2)
  return "G"  if matchable(source, G, 3)
end


while input = $stdin.gets
  figure = Array.new
  figure << input.to_i(2)
  7.times{
    figure << $stdin.gets.to_i(2)
  }
  puts findFigure(figure)
  input = gets
end