IF this text, then This number

I have one cell that contains up to 26 different 3 letter facility prefixes, and they are part of 4 different locations with a number code. Example, ASK is part of Facility code 20. I want a formula that will look at cell M and if it the facility belongs to code 18, 20, 21, or 22, it will put that number in Cell N.

I tried to just repeat this formula 26 times in Column N, but Excel says I have too many arguments.

=IF(M2="ASK","20")

here's my first attempt with the 8 codes that belong to #20:

=IF(M2="ASK","20",IF(M2="BOI","20"),IF(M2="SPO","20"),IF(M2="WHC","20"),IF(M2="WAL","20"),IF(M2="ROS","20"))

When I tried that, the result in column N became 0. if the text in cell M is either of those, I want the result to be 20. then I want to also add a condition that if the text equals other facilities, I want the text to be 21 and so on.

Thanks.... the formlul =MIN(SUMPRODUCT(--(M2={"ASK";"BOI";"SPO";"WHC";"WAL";"ROS"})),1)*20

worked, except I guess I forgot to mention that I have 4 conditions; If M2 = any of those ones I want it to come back with 20, but if it equals any of the other conditions, I want it to come back with those numbers...but how do I put the four conditions together without overwhelming Excel? See, I have either of these conditions and I need them to put the # in cell N...

=MIN(SUMPRODUCT(--(M2={"ASK";"BOI";"SPO";"WHC";"WAL";"ROS"})),1)*20
=MIN(SUMPRODUCT(--(M2={"SNV";"LOM";"LBH";"SDI";"WLA"})),1)*22
=MIN(SUMPRODUCT(--(M2={"WTX";"NMX";"NAZ";"AMA";"PHO";"ELP";"ELP"})),1)*18
=MIN(SUMPRODUCT(--(M2={"PAL";"HON";"NCA";"SFR";"CCA";"SIE"})),1)*21

The best bet is to build a lookup table in an available area, say O2:P25
O2:O25 = Ask Boi Spo Whc etc...
P2:P25 is their corresponding Group #s, 18, 20,21,22 etc..

Then
=VLOOKUP(M2,$O$2:$P$25,2,FALSE)


This makes it so much easier to add/remove/edit items from the groups..

Thanks Everyone, both Tsjallie and mehmetcik, your suggestions worked.

I need to learn more about Vlookup though, that seems more flexible f