 - if Ukrainian army has de-facto control over at least 50% of Crimea territory, and Russia had NOT used tactical nor strategic nuclear weapons against Ukraine before that day, and not uses them for at least 4 weeks after that day.

 - if Ukrainian army has de-facto control over at least 50% of Crimea territory, and Russia had used tactical or strategic nuclear weapons against Ukraine before that day or within 4 weeks after that day.

 - If the war ends before Crimea is liberated by Ukranian forces, including the case where Crimea is returned to Ukraine as part of a peace deal.

The intention to estimate whether Russia is likely to use nukes to prevent loosing Crimea.