import matplotlib.pyplot as plt

def plot_img_and_mask(img, mask):

    classes = mask.max() + 1

    fig, ax = plt.subplots(1, classes + 1)

    ax[0].set_title('Input image')

    ax[0].imshow(img)

    for i in range(classes):

        ax[i + 1].set_title(f'Mask (class {i + 1})')

        ax[i + 1].imshow(mask == i)

    plt.xticks([]), plt.yticks([])

    plt.show()