Could Someone help me with List problem

[alexsendlegames100]

import math

A = list(map(int, input()))

B = list(map(int, input()))

#C = list(map(int, input()))

if A,B < len(3):
   print(D_1)
else:
    print(D_2)


D_1 = math.sqrt( (B[0]-A[0])**2 + (B[1]-A[1])**2 + (B[2]-A[2])**2 )

D_2 = math.sqrt( (B[0]-A[0])**2 + (B[1]-A[1])**2 )

i tried to create a code that will calculate the distance between two points and it succeed but when i try to do the conditional part to make two option if the vector has two values x and y it will print D_2 and if it has x y z it will print D_1 but it shows a lot of mistakes i dont know how to state the a condition which will check the amount of values in the lists and print one of two solution according the amount of values there 3 or less???

[menator01]

One way to check the length of a list

#! /usr/bin/env python3

print('Enter two or three numbers seperated by a space')
while True:

    A = input('>> ').split()

    if len(A) == 3:
        print(f'A has {len(A)} elements')
        print(A)
        break;
    elif len(A) == 2:
        print(f'A has {len(A)} elements')
        print(A)
        break
    else:
        print('Please enter either 2 or three numbers seperated by a space')
        continue

Output:
Enter two or three numbers seperated by a space
>> 5
Please enter either two or three numbers seperated by a space
>> 6 2
A has 2 elements
['6', '2']