class CPU
  attr_reader :jumps, :steps
  attr_accessor :stranger_jumps

  def initialize(jumps)
    @jumps = jumps
    @pc = 0
    @steps = 0
  end

  def self.for(string)
    new string.split.map(&:to_i)
  end

  def step!
    @steps += 1
    if stranger_jumps && jumps[@pc] >= 3
      jumps[@pc] -= 1
      @pc += jumps[@pc] + 1
    else
      jumps[@pc] += 1
      @pc += jumps[@pc] - 1
    end
  end

  def run!
    step! until done_running?
  end

  def done_running?
    @pc < 0 || @pc >= jumps.length
  end
end

jump_string = STDIN.read.chomp

cpu = CPU.for jump_string
cpu_2 = CPU.new cpu.jumps.clone
cpu.run!

part_1 = cpu.steps
puts "Part 1: #{part_1}"

cpu_2.stranger_jumps = true
cpu_2.run!

part_2 = cpu_2.steps
puts "Part 2: #{part_2}"