InputBox to Copy Data from 1 of 2 Worksheets & Paste in Another

[new123]

Depending on the situation, I need to copy and paste reference data from either Sheet1 or Sheet2 and paste into Sheet3. How would I code it such that the user will be able to select where to retrieve the reference data from...Sheet1 or Sheet2? I know I can code it so that the user has to manually type in "Sheet1" or "Sheet2" in the input box, but I'd like to be able to click on a button or the worksheet itself (the names are a little more complex than "Sheet1" and "Sheet2" and manual entry has the potential for error).