#!/usr/bin/env python3
import math as mt
import time
from sys import argv
# ......................................... Read Number from Keyboard
num=argv[1]
start=time.time()
# ........................ Convert String to Integer and Count Digits
n=int(num)
print(f'digits: {len(num):d}')
# ..................................... Upper Limit to Largest Factor
sqnf=mt.isqrt(n)
# ...................................... Create Empty List of Factors
factors=[]
# ........................................... Check if Divisible by 2
while n%2==0:
  factors.append(2)
  n=n//2
  sqnf=mt.ceil(mt.sqrt(float(n)))
# ................................. Check if Divisible by Odd Numbers
i=3
while i<=sqnf:
  while n%i==0:
    factors.append(i)
    n=n//i
    sqnf=mt.isqrt(n)
  i+=2
# ....................................................... Last Factor
if n!=1:
  factors.append(n)
# ..................................................... Print Results
print(factors)
elapsed=time.time()-start
print(f'elapsed time: {elapsed:f} s\n')