public class CheckPassword {
	
	public String rule1(String pw){
		if( pw.length() < 6 || pw.length() > 15) return "1";
		return "";
	}
	// I combined rue 2 and 3 together.
	public String rule23(String pw){
		if(pw.length() == 0) return "";
		int ccount=0;
		int dcount = 0;
		for(int i=0;i<pw.length();i++){
			char c = pw.charAt(i);
			if(c >=65 && c <=90) ccount++;
			else if(c >=97 && c <=122) ccount++;
			else if(c >=48 && c<=57) dcount++;			
		}
		if(dcount == 0) return "2";
		if(ccount ==0) return "3";
		return "";
	}	
	public String rule4(String pw){
		if(pw.endsWith("99")){
			String s = rule23(pw.substring(0,pw.length() -2));
			if(s.equals("2")) return "4";
		}
		return "";
	}
	
	public String checkPassword(String pw){
		String ret1 = rule1(pw);
		String ret2= rule23(pw);
		String ret3 = rule4(pw);
		String res = "";
		if(!ret1.equals("")) res = ret1;
		if(!ret2.equals("")) res += "," + ret2;
		if(!ret3.equals("")) res+="," + ret3;
		if(res.equals("")) return "valid password";
		else return "not a valid password (rule(s) " + res + " violated";
	}
	
	public static void main(String[] args){
		String[] str = {"NPC2006","CGI","a199","99","CGI99"};
		CheckPassword cp = new CheckPassword();
		for(int i=0;i<str.length;i++)
			System.out.println(cp.checkPassword(str[i]));
			
	}
}