int findID(FILE *in, char* String) {
        char line[256];
        char line2[256];
        fgets(line, 256, in);

        char* newString = trim(line);
        if(strcmp("expr term", String) == 0)
                return findID(in, newString);
        else if(strcmp("expr expr - term", String) == 0)
                return findID(in, newString) - findID(in, trim(fgets(line2, 256, in)));
        else if(strcmp("term ( expr )", String) == 0)
                return findID(in, newString);
        else if(strcmp("term id", String) == 0){
                return 42;
        }
}