program mdet
      real*8 GETDET
      real*8,allocatable::A(:,:)
      write(6,*)'dimension:'
      read(5,*)N
      allocate(A(N,N))
      do 1 i=1,N
      write(6,*)'Line ',i,':'
1     read(5,*)(A(i,j),j=1,N)
      write(6,*)'Determinant:',GETDET(A,N)
      end

      REAL*8 FUNCTION GETDET(A,N)
      IMPLICIT none
      integer*4 N,I,J,K
      logical DETEXISTS
      real*8 A(N,N),M,TEMP,L
      real*8, allocatable::ELEM(:,:)
      allocate(ELEM(N,N))
      DO 1 I=1,N 
      DO 1 J=1,N 
1     ELEM(I,J)=A(I,J)
      DETEXISTS=.TRUE.
      L=1.0d0
      DO 2 K=1,N-1
      IF(DABS(ELEM(K,K)).LE.1.0D-20)THEN
       DETEXISTS=.FALSE.
       DO 3 I=K+1,N
       IF(ELEM(I,K).NE.0.0d0)THEN
        DO 4 J=1,N
        TEMP=ELEM(I,J)
        ELEM(I,J)=ELEM(K,J)
4       ELEM(K,J)=TEMP
        DETEXISTS=.TRUE.
        L=-L
        EXIT
       ENDIF
3      CONTINUE
       IF (DETEXISTS.EQV..FALSE.)THEN 
        GETDET = 0.0d0
        RETURN
       ENDIF
      ENDIF
      DO 2 J=K+1,N
      M=ELEM(J,K)/ELEM(K,K)
      DO 2 I=K+1,N
2     ELEM(J,I)=ELEM(J,I)-M*ELEM(K,I)
      GETDET =L
      DO 5 I=1,N
5     GETDET=GETDET*ELEM(I,I)
      RETURN
      END