An exception to this is the abacus (Lambek (1961), Minsky (1961)) counter machine models—every instruction has at least one "next" instruction identifier "z", and the conditional branch has two.
有个例外是算盘（Lambek (1961), Minksy (1961)）计数器机模型——所有指令都有至少一个“下一个”指令标识符"z"，而条件分支有两个。