Looking value in another sheet and returns the ID

Hi All,

I have excel file in that i have 2 sheets S1 (orange) & S2 (blue). I have CID column in S2 and I want to check D column value of S2 in C column of S1 and then i want to return the ID in CID column

for example, I have 5 entries in S2 sheet

and in S1 i have this 

CONCAT2ID

So I want the result in S2 to be

CONCAT1                                                                              CID

i have added excel sheet as well for your reference. Thanks 🙂