import PrelShow ( showSignedInt, showSpace )
import PrelRead ( readDec )
import PrelIOBase ( unsafePerformIO, stToIO )
import PrelArr ( STRef, newSTRef, readSTRef, writeSTRef )
import PrelShow ( showSignedInt, showSpace )
import PrelRead ( readDec )
import PrelIOBase ( unsafePerformIO, stToIO )
import PrelArr ( STRef, newSTRef, readSTRef, writeSTRef )