Python Beginner: TypeError: unsupported operand type(s) for /: 'str' and 'int'

Hi I'm new in Python and machine learning, I need some help with with this issue I get. Thanks a lot for your help!

# Autodaten einlesen
cars = pd.read_csv('C:/Users/tis/Desktop/Projekte/Promotion/Python 
Test/auto-mpg.data', header=None, sep='\s+')


# Verbrauchswerte extrahieren
y = cars.iloc[:,0].values

# Leistungswerte extrahieren
X = cars.iloc[:,[3]].values

# Plot erstellen
g = sns.regplot(x=X, y=y, fit_reg=False)

# Einfache lineare Regression
reg = linear_model.LinearRegression()
reg.fit(X,y)
plt.plot(X, reg.predict(X), color='red')

# Plot beschriften
plt.xlabel('Leistung [hp]')
plt.ylabel('Verbrauch [mpg]')

# Plot anzeigen
plt.show()