A pharmacist is making a mixture of several ingredients. She needs to know the density of the resulting mixture. Density is defined as the mass of the mixture divided by its volume.
You're given a String ingredients, each element of which describes a single ingredient and is formatted "<Volume> ml of <Name>, weighing <Mass> g" (quotes for clarity). <Volume> and <Mass> are integers representing the volume in milliliters and mass in grams, respectively. <Name> is the name of the ingredient.
Return the density of the resulting mixture in grams per milliliters.
|-||The returned value must be accurate to within a relative or absolute value of 1E-9.|
|-||ingredients will contain between 1 and 50 elements, inclusive.|
|-||Each element of ingredients will contain between 23 and 50 characters, inclusive.|
|-||Each element of ingredients will be formatted as described in the statement.|
|-||Each <Volume> in ingredients will be an integer between 1 and 1000, inclusive, with no leading zeroes.|
|-||Each <Mass> in ingredients will be an integer between 1 and 1000, inclusive, with no leading zeroes.|
|-||Each <Name> in ingredients will contain only lowercase letters ('a'-'z') and spaces (' ').|
|-||Each <Name> in ingredients will begin and end with a lowercase letter.|