PROGRAM neliosumma
  IMPLICIT NONE
  WRITE (*,*) 'tulos: ', nesu(1.0)
  WRITE (*,*) 'tulos: ', nesu(2.0)
CONTAINS
  REAL FUNCTION nesu(x)
    IMPLICIT NONE
    REAL, INTENT(IN) :: x
    REAL, SAVE :: nsum = 0.0
    nsum = nsum + x**2
    nesu = nsum
  END FUNCTION nesu
END PROGRAM neliosumma