import math
n=”600851475143”
if n mod 2=0
then
lastFactor=2
n=n div 2
while n mod 2=0
n=n div 2
else
lastFactor=1
factor=3
maxFactor=math.sqrt(n)
while n>1 and factor<=maxFactor
if n mod factor=0
then
n=n div factor
lastFactor=factor
while n mod factor=0
n=n div factor
maxFactor=math.sqrt(n)
factor=factor+2
if n=1
then
output lastFactor
else
output n