A highlighted line covered in gray

You are polishing a line chart of June–September rainfall in three cities. The goal was to highlight only the Busan line, which the title is about, in orange #D55E00, and to push the other two cities into the background in gray #BBBBBB. But when you run the code, all three lines are gray.

Change two lines of code so that only the Busan line is orange. Keep the values, the order in which the lines are drawn, the title, and the legend as they are.

Code to fix

import matplotlib.pyplot as plt

months = ["Jun", "Jul", "Aug", "Sep"]
rain = {
    "Seoul": [130, 410, 330, 140],
    "Busan": [190, 280, 250, 260],
    "Jeju": [220, 230, 270, 210],
}

fig, ax = plt.subplots()
for city, values in rain.items():
    ax.plot(months, values, marker="o", label=city)
ax.lines[2].set(color="#D55E00", linewidth=3)
for line in ax.lines:
    line.set(color="#BBBBBB")
ax.set_title("Busan had the most rain in September")
ax.set_ylabel("Rainfall (mm)")
ax.legend()
plt.show()