DIGITS = 5000
ARRAYLEN = (DIGITS * 10) // 3 + 1
array = [2]*ARRAYLEN
predigits = Array(Int32).new()
pi = Array(Int32).new()

digit = 0
until digit==DIGITS
  index = 0
  array = array.map! {|x| x*10}
  until index==ARRAYLEN-1
    numer = ARRAYLEN - index - 1
    denom = numer * 2 + 1

    array[index + 1] += (array[index] // denom) * numer
    array[index] %= denom

    index += 1
  end

  quot = array[-1] // 10

  case quot
  when 9
    predigits << 9
  when 10
    print predigits.map!{|x|(x+1)%10}.join("")
#    pi += predigits.map!{ |x| (x+1)%10}
    predigits = [0]
  else
    print predigits.join("")
#    pi += predigits
    predigits = [quot]
  end

  array[-1] %= 10
  digit += 1
end

# puts pi.join("")
puts ""