it's very difficult, i imagine you'd have to be near genius level to get this done in any short amount of time. Generally a couple of letters are given, depending on their value in the quote, there can be up to 5 letters given. E.g. the letter "A" and the letter "I" are very strong, so you would only need one more letter, however the letter "H" for example is weak, so you may need a few others or stronger ones.
by strong and weak i'm meaning in the English language different letters are used more than other, and can be put in smaller words, or even by them selves, weaker one's don't appear very often, and have to be accompanied by many other letters in many cases. such as "K".
Often vowels are strong as they appear frequently, so giving atleast one of those in them will help out incredibly.
Thanks for reading.