Why do 2 histograms overlap in matplotlib?

In this python script is an attempt to create two histogram in one figure but the second histogram overlaps the first one

from random import randrange
import matplotlib.pyplot as plt

fig = plt.figure(figsize=(50,50))
ids =  [str(randrange(10000, 99999)) for i in range(1000)]
ids2 = [str(randrange(10000, 99999)) for i in range(1000)]
def fun1():
    ax = fig.add_subplot(1, 1, 1)
    n, bins, patches = ax.hist(x=ids, bins=range(500))
    ax.grid(axis='y', alpha=0.6)
    fig.tight_layout(pad=3.0, w_pad=2.0, h_pad=2.0)

def fun2():
    ax2 = fig.add_subplot(2, 1, 2)
    n, bins, patches = ax2.hist(x=ids2, bins=range(500))
    ax2.grid(axis='y', alpha=0.6)
  
fun1()
fun2()

Although I used tight_layout this does not help with the overlapping of the two histograms.