At least how many cups of graham cracker crumbs does the recipe "Raspberry Chiffon Pie" need?
'graham cracker crumbs' is a name of an ingredient; 'Raspberry Chiffon Pie' refers to title
SELECT T2.min_qty FROM Recipe AS T1 INNER JOIN Quantity AS T2 ON T1.recipe_id = T2.recipe_id INNER JOIN Ingredient AS T3 ON T3.ingredient_id = T2.ingredient_id WHERE T1.title = 'Raspberry Chiffon Pie' AND T3.name = 'graham cracker crumbs'