Copying and Pasting Long Formula from Word into Excel Cell

Hello,

I'm trying to paste a formula (fairly simple - lots of the IF function) that I developed in Word for simplicity's sake into a cell in Excel. When I get it all in there and press enter, I get the following:

"Text Values in formulas are limited to 255 characters. To create text values longer than 255 characters in a formula, use the CONCATENATE function or the CONCATENATE operator (&)."

I know I can make a formula of this length (when I first built the formula, I did it within Excel, and it was longer than the current iteration) in Excel, so is there any solution short of typing out the whole thing into Excel (will take half an hour and likely errors...)?

Any advice?