shelves

$count
[1] 2

$total
[1] 450

$arr
[1] 300 150

[1] "impossible"
$count
[1] 13

$total
[1] 12274

$arr
 [1] 995 987 985 972 957 947 935 935 917 914 913 910 907

[[1]]
[[1]]$count
[1] 2

[[1]]$total
[1] 450

[[1]]$arr
[1] 300 150


[[2]]
[1] "impossible"

[[3]]
[[3]]$count
[1] 13

[[3]]$total
[1] 12274

[[3]]$arr
 [1] 995 987 985 972 957 947 935 935 917 914 913 910 907