By the entrances of the Girls' Dormitory and Library there are flowered areas, just walk up and it should say pick flowers. Press Y to pick a flower. You can only hold ten flowers at a time so go up to a girl (or boy) and give them the flowers to empty your inventory, then repeat until you've picked 50.

**You can check how many flowers you have picked:**
Start---> Stats---> General---> Objects & Items---> Flowers Found

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