program day1
implicit none
integer :: i, j
integer, dimension(200) :: input
open(10, file='input', status='old')
do i = 1, 200
read(10, *) input(i)
end do
close(10)
do i = 1, 200
do j = 1, 200
if (input(i) + input(j) == 2020) then
print *, input(i) * input(j)
stop
end if
end do
end do
end program day1