import numpy as np
import matplotlib.pyplot as plt

X = ['Group A','Group B','Group C','Group D']
Ygirls = [10,20,20,40]
Zboys = [20,30,25,30]

X_axis = np.arange(len(X))

plt.bar(X_axis - 0.2, Ygirls, 0.4, label = 'Girls')
plt.bar(X_axis + 0.2, Zboys, 0.4, label = 'Boys')

plt.xticks(X_axis, X)
plt.xlabel("Groups")
plt.ylabel("Number of Students")
plt.title("Number of Students in each group")
plt.legend()
plt.show()