ふたつにひとつ
one of two (possibilities, alternatives, etc.)
Also written ２つに１つ
Expression
可能性かのうせいは中立ちゅうりつか戦争せんそうかの二ふたつに一ひとつだ。
The alternative possibilities are neutrality or war.
できることは抵抗ていこうか逃亡とうぼうか二ふたつに一ひとつだった。
The alternative possibilities were resistance and flight.
我々われわれは行いくかとどまるか２つに１つだ。
We have the alternative of going or staying.