Snakemake: Tranverse DAG depth-first?

One way I can come up with is by setting priorities for each rule:

rule all:
    input:
        ["third_a.txt", "third_b.txt", "third_c.txt"]

rule first:
    output:
        touch("first_{sample}.txt")
    priority: 1

rule second:
    input:
        rules.first.output
    output:
        touch("second_{sample}.txt")
    priority: 2

rule third:
    input:
        rules.second.output
    output:
        touch("third_{sample}.txt")
    priority: 3

and if you now run it with snakemake -j 1 it is executed depth-first!