<s>
Software	B-Application
as	I-Application
a	I-Application
product	I-Application
(	O
SaaP	O
,	O
also	O
programming	B-Application
product	I-Application
,	O
software	O
product	O
)	O
is	O
a	O
product	O
,	O
software	O
,	O
which	O
is	O
made	O
to	O
be	O
sold	O
to	O
users	O
,	O
and	O
users	O
pay	O
for	O
licence	B-License
which	O
allows	O
them	O
to	O
use	O
it	O
,	O
in	O
contrast	O
to	O
SaaS	B-Architecture
,	O
where	O
users	O
buy	O
subscription	O
and	O
where	O
the	O
software	O
is	O
centrally	O
hosted	O
.	O
</s>
<s>
One	O
example	O
of	O
software	B-Application
as	I-Application
a	I-Application
product	I-Application
has	O
historically	O
been	O
Microsoft	B-Application
Office	I-Application
,	O
which	O
has	O
traditionally	O
been	O
distributed	O
as	O
a	O
file	O
package	O
using	O
CD-ROM	O
or	O
other	O
physical	O
media	O
or	O
is	O
downloaded	O
over	O
network	O
.	O
</s>
<s>
Office	B-Operating_System
365	I-Operating_System
,	O
on	O
the	O
other	O
hand	O
,	O
is	O
an	O
example	O
of	O
SaaS	B-Architecture
,	O
where	O
a	O
monthly	O
subscription	O
is	O
required	O
.	O
</s>
<s>
In	O
the	O
book	O
The	O
Mythical	O
Man-Month	O
Fred	O
Brooks	O
tells	O
that	O
when	O
estimating	O
project	O
times	O
,	O
it	O
should	O
be	O
remembered	O
that	O
programming	B-Application
products	I-Application
(	O
which	O
can	O
be	O
sold	O
to	O
paying	O
customers	O
)	O
are	O
three	O
times	O
as	O
hard	O
to	O
write	O
as	O
simple	O
independent	O
in-house	O
programs	O
,	O
because	O
requirement	O
to	O
work	O
on	O
different	O
situations	O
,	O
which	O
increases	O
testing	O
efforts	O
and	O
as	O
a	O
documentation	O
.	O
</s>
