problem definind a function

hello, Does anybody know why it is not possible to define the folowing function in ghc? gggg= \x y -> (x+y - length [1..(gcd x y)] >= round ((x+1)/2)) ) The message obtained was this one: No instance for (RealFrac Int) arising from use of `round' at num-s-divs.hs:253 In the second argument of `(>=)', namely `round ((x + 1) / 2)' In a lambda abstraction: (((x + y) - (length [1 .. (gcd x y)])) >= (round ((x + 1) / 2))) Thanks in advance, J. I. García