public static void main(String[] args) {
        String s1 = "welcomeback";
        String s2 = "bac";
        int found = -1;
        String temp;
        for (int i = 0; i < (s1.length() - (s2.length() - 1));i++) {
            temp = "";
            if(s1.charAt(i) == s2.charAt(0))
                for (int j = 0; j < s2.length(); j++) {
                    temp = temp + s1.charAt(i+j);
                }
            if(temp.equals(s2)) {
                found = i;
                break;
            }
        }

        String subString = "";
        if(found != -1) {
        for (int i = 0; i < found; i++) {
            subString = subString + s1.charAt(i);
        }

        for (int i = found + s2.length(); i < s1.length(); i++) {
            subString = subString + s1.charAt(i);
        }
        System.out.println(subString);

        }
        else {
            System.out.println("-1");
        }


    }