# t20
# C4B:    |[x,y]| + |[y,x]|
# eocimp: [-x + y | -x + y ≥ 0] + [x + -y | x + -y ≥ 0]

def startT20():
  var x, y

  while x < y:
    tick 1
    x = x + 1

  while y < x:
    tick 1
    y = y + 1