!Keyword: pre-emptive goal programming, 
!  lexico-goal programming, staff scheduling;
MIN     COST - EXTRA
  SUBJECT TO
     MON)   M + R + F + S + N - XM >=   3
     TUE)   M + F + S + N + T - XT >=   3
     WED)   M + S + N + T + W - XW >=   8
     THU)   M + R + N + T + W - XR >=   8
     FRI)   M + R + F + T + W - XF >=   8
     SAT)   R + F + S + T + W - XS >=   3
     SUN)   R + F + S + N + W - XN >=   3
      XM)   XM <=   1
      XT)   XT <=   1
      XW)   XW <=   1
      XR)   XR <=   1
      XF)   XF <=   1
      XS)   XS <=   1
      XN)   XN <=   1
! Define the two objectives;
    COST)  COST - M - R - F - S - N - T - W =    0
   EXTRA)  EXTRA - XM - XT - XW - XR - XF - XS - XN =  0
 END
  FREE     COST
  FREE    EXTRA

