def calculation(a, b, n)
  result = (a/b).to_s
  point = result.index(".")

  sum = 0
  for i in 0..n do
    if i == result.size
      break
    end
    sum += (result[i+point, 1]).to_i
  end
  
  return sum
end

while input = gets
  values = (input.chomp).split(' ')
  puts calculation(values[0].to_f, values[1].to_f, values[2].to_f)
end