TDIST equation

I'm trying to run a TDIST test. I am using = TDIST(E4,E3-2,2)

E4 is 2.34. E3 is 45. When I was giving the formula, I was told that there should be a - in front of the E4, like this:

= TDIST(-E4,E3-2,2)

When I do that, I get an error. Is my formula above correct?