Unhandled exception at 0x001D6653 in Lid.exe: 0xc0000094: integer division by zero - fortran

Question

I am trying to write the code for Lid-Driven Cavity in Fortran.
When I want to run the code, suddenly the integer division by zero errors appears.
I know what is the problem but I don't know how I can solve it. I even changed some numbers in order to avoid this issue but again happened.
I uploaded the photo of the error
I searched about it and there are some answers for C++ but I could not find anything for Fortran.
Program Lid
implicit none
Integer :: I,J,nx, ny, dx, dy, L, W, Iteration, Max_Iteration , Re, M, N, dt
Real :: Delta
Real, allocatable :: u(:,:), v(:,:), p(:,:), u_old(:,:), v_old(:,:), p_old(:,:), X(:), Y(:)
!***************************************************!
PRINT *, "ENTER THE DESIRED POINTS ..."
PRINT *, "... IN X DIRECTION: SUGGESTED RANGE (20-200)"
READ*, M
PRINT *, "... IN Y DIRECTION: SUGGESTED RANGE (10-100)"
READ*, N
! Define Geometry
dt = 0.001
Delta = 2
Re = 100
L = 10
W = 10
dx = L /Real(M-1)
dy = W /Real(N-1)
ALLOCATE (X(M),Y(N),u(M,N),u_old(M,N),v(M,N),v_old(M,N),p(M,N),p_old(M,N))
! Grid Generation
Do I = 1, M
x(I) = (I-1)* dx
End Do
Do J=1 , N
y(J) = (J-1) * dy
End Do
! Boundray Condition
Do I=1 , M
u(I,1) = 0
u(1,I) = 0
u(M,I) = 0
u(I,M) = 1 ! Lid Velocity
End Do
Do J=1, N
v(J,1) = 0
v(1,J) = 0
v(J,N) = 0
v(M,J) = 0
End Do
! Initialization
Do I=2, M-1
Do J=2, N-1
u(I,J) = 0
v(I,J) = 0
p(I,J) = 0
End Do
End Do
! Solver
Do I=2, M-1
Do J=2, N-1
u_old(I,J) = u(I,J)
v_old(I,J) = v(I,J)
p_old(I,J) = p(I,J)
u(I,J) = - dt / 4* dx * (( u(I, J+1)+ u_old(I,J))**2 - (u_old(I, J)+u(I,J-1))**2) - dt / 4* dy * ((u_old(I,J)+ u(I-1,J)) &
* (v(I-1,J) + v(I-1, J+1)) - (u_old(I,J) + u(I+1,J)) * (v_old(I,J) + v(I,J+1))) - dt / dx *(p(I, J+1) - p(I,J)) &
+ dt / Re * ((u(I+1,J) - 2 * u_old(I,J) + u(I-1,J)) / dx**2 + (u(I,J+1) - 2 * u_old(I,J) + u(I,J+1)) / dy**2) + u_old(I,J)
v(I,J) = - dt / 4* dy * (( v(I-1, J)+ v(I-1,J+1))**2 - (v_old(I, J)+v(I,J+1))**2) - dt / 4* dx * ((u_old(I,J)+ u(I,J+1)) &
* (v(I,J+1) + v(I-1, J+1)) - (u_old(I,J) + u(I,J-1)) * (v_old(I,J) + v(I-1,J))) - dt / dy *(p(I, J+1) - p(I,J)) &
+ dt / Re * ((v(I+1,J) - 2 * v_old(I,J) + v(I-1,J)) / dx**2 + (v(I,J+1) - 2 * v_old(I,J) + v(I,J+1)) / dy**2) + v_old(I,J)
p(I,J) = - Delta * dt / 2 * ((u(I,J+1)+ u_old(I,J)) - (u_old(I,J) + u(I,J-1))) - Delta * dt / 2 &
* ((v(I-1,J)+ v(I-1,J+1)) - (v_old(I,J) + v(I,J+1)))
End Do
End Do
!-----------------------OUTPUTS GENERATION-----------------------------
OPEN (1,FILE='FIELD.PLT')
WRITE (1,*) 'VARIABLES=X,Y,u,v,p'
WRITE (1,*) 'ZONE I=',M,' J=',N
DO J=1,N
DO I=1,M
WRITE (1,*) X(I),Y(J),u(I,J),v(I,J),p(I,J)
END DO
END DO
End Program Lid

Answer 1

Assuming that the yellow arrow shown on the image indicates the line (72) where the exception occurred:
Apparently dx is or becomes zero, because that's the only devision done on that line.
You must know what it means when dx is zero or what causes it, unless it's a programming or data input issue that causes it.
In any case you must make sure that you don't execute that part of your code that divides by zero.
What you need to do to prevent this, fully depends on what your code is supposed to do. I can't help you with that.