C=1
Cb=1e7

def f3(x):
    return 1 - C*x/Cb

import numpy as np
import json
import matplotlib.pyplot as plt

colorList = json.load(open('color/config.json','r'))["color"]

plt.plot(np.arange(1e6,5e6,1e5),f3(np.arange(1e6,5e6,1e5)),label='Isoc',color=colorList[0])
plt.xlabel('total passengers')
plt.ylabel('Isoc')
plt.legend()
plt.show()