ご意見ありがとうございました。更新したスクリプトはこちらです：

```
    import random
    import matplotlib.pyplot as plt
    import sys
    
    if len(sys.argv) != 2:
        print('Usage: python test.py <number of rolls>')
        sys.exit(1)
    
    num_rolls = int(sys.argv[1])
    
    rolls = []
    for i in range(num_rolls):
        dice = [random.randint(1, 20) for _ in range(3)]
        rolls.append(sum(sorted(dice)[1:]))
    
    plt.hist(rolls, bins=range(2, 41))
    plt.xlabel('Sum of two highest rolls')
    plt.ylabel('Frequency')
    plt.title('Histogram of dice rolls')
    plt.show()
```

他に何か変更してほしいところはありますか？
Thank you for your feedback. Here is the updated script: 

    import random
    import matplotlib.pyplot as plt
    import sys
    
    if len(sys.argv) != 2:
        print('Usage: python test.py <number of rolls>')
        sys.exit(1)
    
    num_rolls = int(sys.argv[1])
    
    rolls = []
    for i in range(num_rolls):
        dice = [random.randint(1, 20) for _ in range(3)]
        rolls.append(sum(sorted(dice)[1:]))
    
    plt.hist(rolls, bins=range(2, 41))
    plt.xlabel('Sum of two highest rolls')
    plt.ylabel('Frequency')
    plt.title('Histogram of dice rolls')
    plt.show()

Are there any other changes you would like me to make to it?