pirobos codigo incompleto !!!

public class Parcial_4 {

    public static void main(String[] args) {

        int i = 'a'-87;



    }

    static int conversion(String s){
        char d0 = s.charAt(3);
        char d1=s.charAt(2);
        char d2=s.charAt(1);
        char d3=s.charAt(0);
        int i = 'a'-87;
        int j = 'b'-87;
        int k = 'c'-87;
        int l = 'd'-87;
        int m = 'e'-87;
        int n = 'f'-87;


        }
    }