what's the difference between if not 3 in [1,2,4,5]: and if 3 not in [1,2,4,5]?

Question

I'm new to python,so kindly please can anybody explain the difference between

if not 3 in [1,2,4,5]:
    print("true")

and

if 3 not in [1,2,4,5]:
    print("true")