What's making the difference here? I just dont get behind it

So i made this code to check if to integers can be devided without a rest, and its working. But I needed to make a change so it works. I really just want to understand why this little change completely inversed the outcome of my code. This is the working code

x = input("Erster Teiler")
y = input("Zweiter Teiler")

z = int(x)%int(y) 
z1 =int(y)%int(x)

if z == 0 or z1 == 0:
    print("teilbar")
else: 
    print("nicht teilbar")

my first attempt at this excercie is doing the exact oppossite. If i put in 2 numbers that you can not divide, it says they are divisable. I just want to know what makes the difference in these codes. As you can see all i did was changing the premise for my first if-condition.

x = input("Erster Teiler")
y = input("Zweiter Teiler")

z = int(x)%int(y) 
z1 =int(y)%int(x)

if z or z1 == 0:
    print("teilbar")
else:
    print("nicht teilbar")