MAX_K = 1000000
k = 0
n = 0
while k < MAX_K
n += 1
k += (Math.log10(n) + 1).to_i
end
answer = n.to_s.reverse[(k - MAX_K), 1]
puts "answer is #{answer} (of #{n} #{n.to_s.length - (k - MAX_K)} th)"
TUFYX0sgPSAxMDAwMDAwCmsgPSAwCm4gPSAwCgp3aGlsZSBrIDwgTUFYX0sKCW4gKz0gMQoJayArPSAoTWF0aC5sb2cxMChuKSArIDEpLnRvX2kKZW5kCgphbnN3ZXIgPSBuLnRvX3MucmV2ZXJzZVsoayAtIE1BWF9LKSwgMV0KCnB1dHMgImFuc3dlciBpcyAje2Fuc3dlcn0gIChvZiAje259ICAje24udG9fcy5sZW5ndGggLSAoayAtIE1BWF9LKX0gdGgpIgo=