To generate a random number by using time - haskell

Question

I would like to generate a number by using Data.Time.Clock.POSIT
test' = do
y <- getPOSIXTime
let w = (tail (take 3 (reverse(show y))))
return w
test2 = do
getseed <- test'
let x = read (getseed)
putStrLn (show(x))
So I use getPOSIXTime to get time with the nanosecond, so I convert it into a string and take the first 3 digits and then convert them back to Int. However, it gives me error like this:
test.hs:156:14: error:
• Ambiguous type variable ‘a0’ arising from a use of ‘read’
prevents the constraint ‘(Read a0)’ from being solved.
Relevant bindings include x :: a0 (bound at test.hs:156:10)
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance Read GeneralCategory -- Defined in ‘GHC.Read’
instance Read Ordering -- Defined in ‘GHC.Read’
instance Read Integer -- Defined in ‘GHC.Read’
...plus 23 others
...plus 12 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: read (getseed)
In an equation for ‘x’: x = read (getseed)
In the expression:
do getseed <- test'
let x = read (getseed)
putStrLn (show (x))
|
156 | let x = read (getseed)
| ^^^^^^^^^^^^^^
test.hs:157:16: error:
• Ambiguous type variable ‘a0’ arising from a use of ‘show’
prevents the constraint ‘(Show a0)’ from being solved.
Relevant bindings include x :: a0 (bound at test.hs:156:10)
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance Show GeneralCategory -- Defined in ‘GHC.Unicode’
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
...plus 27 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the first argument of ‘putStrLn’, namely ‘(show (x))’
In a stmt of a 'do' block: putStrLn (show (x))
In the expression:
do getseed <- test'
let x = read (getseed)
putStrLn (show (x))
|
157 | putStrLn (show(x))
| ^^^^^^^
any help would be appreciated!!