#!/usr/koeki/bin/ruby
# coding: euc-jp

sum = 0
s0 = 1     # 開始
s1 = 100   # 終了
del = 2    # きざみ

print "0"

s0.step(s1, del) do |odd|
  printf(" +%3d", odd)
  sum += odd
end
printf("は %d です\n", sum)