parameter n=100
	real tv(n,n),tu(n,n)
	open(10,file='soojus.in')
	open(20,file='soojus.dat')
	read (10,*) nt,dt,dx,ixsamma,iysamm,alpha,iviz

	do i=1,n
	do j=1,n
	tv(i,j)=0.
	if (i.ge.35.and.i.le.65.and.j.ge.35.and.j.le.65) then
	tv(i,j)=100.
	else
	tv(i,j)=0.
	endif
	tu(i,j)=0.
	enddo
	enddo
	write (20,100) tv
	
	do k=1,nt
	
	do i=1,n
	do j=1,n
	if (i.ge.35.and.i.le.65.and.j.ge.35.and.j.le.65) then
    	tu(i,j)=100.
	elseif(i.eq.1) then
	tu(1,j)=tv(2,j)
	elseif(i.eq.100) then
	tu(100,j)=tv(99,j)
	elseif(j.eq.1) then
	tu(i,1)=tv(i,2)
	elseif(j.eq.100) then
	tu(i,100)=tv(i,99)
	else
	tu(i,j)=tv(i,j)+alpha*dt*(tv(i+1,j)+tv(i-1,j)+tv(i,j+1)+
     *  tv(i,j-1)-4.*tv(i,j))/dx
	endif
	enddo
	enddo
	do i=1,n
	do j=1,n
	tv(i,j)=tu(i,j)
	enddo
	enddo
	
	if ((k/iviz)*iviz.eq.k) then
	write (20,100) tu
	endif
	
100	format (100 f15.6)
	
	enddo
	stop
	end