public static String combine(String s1, String s2) {
    String s3;
    String s4;

    if (s1.length() < 3)
        s3 = s1;
    else
        s3 = s1.substring(0, 1) + s1.substring(s1.length() - 2, s1.length() - 1);

    if (s2.length() < 3)
        s4 = s2;
    else
        s4 = s2.substring(0, 1) + s2.substring(s2.length() - 2, s2.length() - 1);

    return s3 + s4;
}