假定你是南阳一中某班学生李华，对于你们校园中存在的随意涂写（to scribble）和乱丢垃圾（to litter）的行为有感而发，请用英语给你校杨校长写封信。信中应包括以下内容：
1.说明写信目的；
2.对于这些行为进行批评；
3.提出建议。
注意：信的抬头，落款及日期以给出。
Jan26.2013
Dear Head master Yang,
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
Yours faithfully
Li Hua