SUB MIDEXP(FUNK,AA,BB,S,N)
      FUNC(X)=FUNK(-ALOG(X))/X
      B=EXP(-AA)
      A=0.0
      IF N=1 THEN
          S=(B-A)*FUNC(0.5*(A+B))
          IT=1
      ELSE
          TNM=IT
          DEL=(B-A)/(3.*TNM)
          DDEL=DEL+DEL
          X=A+0.5*DEL
          SUM=0.0
          FOR  J=1 TO IT
              SUM=SUM+FUNC(X)
              X=X+DDEL
              SUM=SUM+FUNC(X)
              X=X+DEL
          NEXT J
          S=(S+(B-A)*SUM/TNM)/3.
          IT=3*IT
      ENDIF
  END SUB