char **last_names;
    last_names = malloc(sizeof(char*) * 4);
    last_names[0] = malloc(sizeof(char)* 20);
    last_names[1] = malloc(sizeof(char) * 20);
    last_names[2] = malloc(sizeof(char) * 20);
    last_names[3] = malloc(sizeof(char) * 20);