program test
integer(8) :: nn,k,aa(100),aaa(100),a(100),b(100),c(10000),i,a_min,atai,sig,last(100),j,count,temp


read(*,*) nn,k
read(*,*) (aa(i),i=1,nn)

a(1:nn) = aa(1:nn)

do i = 1,nn
	b(i) = i
enddo

call heapsort2(nn,a(1:nn),b(1:nn))


count = 1

do i = 1,k
	aaa(1:nn) = aa(1:nn)

	if(last(i-1) > 0 )then
		aaa(last(i-1)) = 999
	endif
	
	minimum = 999999
	do j =1,nn
		if(aaa(j) <= minimum) then
			last(i) = j
			minimum = aaa(j)
		endif
	enddo

	do j=1,nn
		if(i==1) then
			if((j .ne. last(i))) then
				c(count) = j
				count = count + 1
			endif
		else
			if((j .ne. last(i-1)) .and. (j .ne. last(i))) then
				c(count) = j
				count = count + 1
			endif
		endif
	enddo

	do j=1,nn
		if(j == last(i)) then
			c(count) = j
			count = count + 1
		endif
	enddo

enddo

	do j=1,nn
		if(j .ne. last(k)) then
			c(count) = j
			count = count + 1
		endif
	enddo

if( sum(a(1:nn))<nn*(k+1)-k .or. a(1)<1+k/2 ) then
	write(*,*) -1
else
	write(*,*) count-1
	write(*,*) c(1:count-1)
endif









contains
 
subroutine heapsort2(n,y1,y2)
 
	implicit none
	integer(8),intent(in) :: n
	integer(8),intent(inout) :: y1(1:n)
	integer(8),intent(inout) :: y2(1:n)
	integer(8) :: i,k,j,l
	integer(8) :: t1,t2
	
	l = n/2+1
	k = n
 
	do while (k /= 1)
		 if(l > 1) then
				l = l-1
				t1 = y1(l)
				t2 = y2(l)
				
		 else
				t1 = y1(k)
				t2 = y2(k)
				y1(k) = y1(1)
				y2(k) = y2(1)
				k = k-1
				if(k == 1) then
					 y1(1) = t1
					 y2(1) = t2
					 exit
				endif
		 endif
 
		 i = l
		 j = l+l
 
		 do while(j <= k)
				if(j < k) then
					 if(y1(j) < y1(j+1)) j = j+1
				endif
				
				if (t1 < y1(j)) then
					 y1(i) = y1(j)
					 y2(i) = y2(j)
					 i = j
					 j = j+j
				else
					 j = k+1
				endif
		 
		 enddo
		 
		 y1(i) = t1
		 y2(i) = t2
	
	enddo
	return
 
end subroutine heapsort2

end program