Solution

   PROGRAM WotKind
    IMPLICIT NONE
    INTEGER :: old, exponent, curr 
     old = SELECTED_INT_KIND(1)
     DO exponent = 2, 32
      curr = SELECTED_INT_KIND(exponent)
      IF ( curr .ne. old ) THEN
       PRINT*, "Kind number", old, " represents numbers &
               &upto 10**",exponent-1
       old = curr
      END IF
      IF ( curr .eq. -1 ) EXIT
     END DO
     PRINT*, "Default kind has kind number", SELECTED_INT_KIND(2)
   END PROGRAM WotKind