def solve(v)
  d = (v[0].to_f / v[1].to_f).to_s.split(".")[1]
  s = 0
  count = 0
  d.each_byte{|c|
    s += c - 48
    break if (count += 1) == v[2].to_i
  }
  return s
end

while input = $stdin.gets
  v = input.chomp.split(" ")
  p solve(v)
end