一ひとつとして

expression, adverb

(not) a single one; (not) any; (not) at all

Used with a negative predicate to emphasize that there is absolutely no instance or amount of something. Often follows a noun or a counter phrase.

• 彼かれの言いうことは一ひとつとして信しんじられない。

  I can't believe a single thing he says.

• この問もん題だいは一ひとつとして簡かん単たんなものはない。

  Not one of these problems is easy.