Automaticly connect content from other sheets

Hi, I'm trying to solve one thing and I hit the 8192 character formula limit when I tried to bring up a formula. Basicly what I'm trying to do is:

1) I open the file and fill in cell C1 on sheet1 with a certain content
2) on sheet2-sheet7 I have content in all the cells a1-a50 and b1-b50
3) if the content from C1 on sheet1 is the same as any cell a1-a50 on sheet2-sheet7, then D1 on sheet1 should automaticly get the content of the b column. That means, if C1 on sheet1 is the same as for example A13 from sheet4, then D1 on sheet1 will automaticly be the same as B13 from sheet4

Probably I'm not really understandable, so I attach an example. I filled in C1 on sheet1. On sheet4 there are already filled the cells a13 and b13. A13 is the same as C1, so D1 will get the same content as B13.

Can somebody please help me what formula to write in D1 on sheet1, so I get the information in this case from b13 from sheet4? Thanks a lot in advance.