S-Ass1-Karatsuba

def divide_and_conquer(x,y):
    if len(str(x)) == 1 or len(str(y)) == 1:
        return x*y
    else:
        n = int(max(len(str(x)), len(str(y))))
        nby2 = int(n / 2)

        a = x // 10**(nby2)
        b = x % 10**(nby2)
        c = y // 10**(nby2)
        d = y % 10**(nby2)

        ac = divide_and_conquer(a,c)
        bd = divide_and_conquer(b,d)
        ad_plus_bc = divide_and_conquer(a+b, c+d) - ac - bd

        prod = ac * 10**(2*nby2) + (ad_plus_bc * 10**nby2) + bd

        return prod

x = int(input("Enter 20 digit num: "))
ans = divide_and_conquer(x, x)
print(f"Square of number {x} is {ans}")