class Start
  def main
    n = input.to_i
    echo solve(n)
    return nil
  end

  protected

  def solve(n)
    m = (n ** 0.5).to_i
    if m ** 2 < n
      while m ** 2 <= n
        m += 1
      end
      m -= 1
    else
      while m ** 2 >= n
        m -= 1
      end
      m += 1
    end

    return m
  end

  def echo(*x)
    print(*x)
    puts
  end

  def input = gets.chomp
end

Start.new.main