Jason is a crystal miner, he has mine some crystals.  He sold $10$ more than half of his crystals to Yvonne.  Then, he mined $20$ more crystals in Singapore. After that, he sold $14$ crystals to Cherlyn. He has $35$ crystals in the end.  How many crystals does he have at first?~\uline{~~~~~~~~~~}~crystals 
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