Hi Ibtissam, an integer can't be at the same time larger than 22 and smaller than 6

you probably want a few or instead of and in there

Hi Ibtissam,

Let's first simplify your condition by replacing the DayOfWeek and Hour by a simple variable:

If(Day > 0 and Day < 6 and (Hour >= 6 and Hour < 14), "A",
If(Day > 0 and Day < 6 and (Hour >= 14 and Hour < 22), "B",
If(Day > 0 and Day < 6 and (Hour >= 22 and Hour < 6), "C",
If(Day = 0 or Day = 6  and (Hour >= 6 and Hour < 18), "WEA",
If(Day = 0 or Day = 6  and (Hour >= 18 and Hour < 6), "WEB",
"Nothing")))))

The first thing I notice is that you repeat the "Day > 0 and Day < 6" three times, and the "Day = 0 or Day = 6" two times. My recommendation would be to simplify that, which makes it faster and much more readible:

if (Day > 0 and Day < 6,
	if (Hour >= 6 and Hour < 14, "A",
	if (Hour >= 14 and Hour < 22, "B",
	if (Hour >= 22 and Hour < 6, "C", "???"))),
// else
	if (Hour >= 6 and Hour < 18, "WEA",
	if (Hour >= 18 and Hour < 6), "WEB", "???")
)

As Dorine already told you, something can't be both be larger than 22 and smaller than 6 (or larger than 18). That's just a logical error in your code. I truely hope you can see that there's an error there. That said, the solution is easy, just do not specify that condition at all but use it as an else:

if (Day > 0 and Day < 6,
	if (Hour >= 6 and Hour < 14, "A",
	if (Hour >= 14 and Hour < 22, "B",
	"C"))),
// else
	if (Hour >= 6 and Hour < 18, "WEA",
	"WEB")
)

Note though that I'd consider this all very, very basic programming skills, so if you feel this is above your head, perhaps you should consider some more training material...