You can be bitter but at least do some basic math before sprouting nonsense.
You couldn't even find the 2nd part of the event with today's technological advances to aid you, plus despite others mentioning several times and providing you links, you fail to open your eyes.
800 crystals is definitely doable even if you only spend the min amount SC gained from the event.
12 stam = 24 Crystals (100% with thief, 90%~ without)
14x2x24 = 672
Using natural stam growth, you can get 600-672 crystals within 2 weeks. You get 17 SC from the event itself.
Thats anywhere from 12-16 stam depending on your level.
17x16= 272 stam or 544 Crystals
With just natural stam+SC from recent events you can get 1.2k~ Crystals if you put your effort into it.
Of course you might want to reduce depending on whether you have thief, and map deviation. (Theres also 100% first drop rate)
Oh a sidenote, theres a 3x exp for female units above gold? Woohoo!