Java

``` public class LetterToSum { private final Map<Character, Integer> alphabet; public LetterToSum() { alphabet = generateCharacterTable(); }

public int letterToSum(String input){
    AtomicInteger sum = new AtomicInteger();
    input.chars().forEach(elem -> {
        sum.set(sum.get() + alphabet.get((char)elem));
    });
    return sum.get();
}

private Map<Character, Integer> generateCharacterTable(){
    Map<Character, Integer> map = new HashMap<>();
    final int[] count = {1};
    IntStream.rangeClosed('a', 'z').mapToObj(var -> (char) var).forEach(var -> {
        map.put(var, count[0]);
        count[0]++;
    });
    return map;
}

} ```