while n = STDIN.gets.split(/ /)
  for i in 0.. 2
    n[i] = n[i].to_i
  end
  o = (n[0]*1.0/n[1]).to_s
  a = 0
  for i in o.index(".")+1.. o.index(".")+n[2]
    if o[i] != nil
      a+=o[i].to_i
    end
  end
  puts a
end