public class Stack { 
   private int array[]; 
   private int max; 
   private int top; 
   public Stack(int max){ 
     this.max = max; 
     array = new int[max]; 
     top = 0; 
   } 
   public void push(int value){ 
     if(isFull()){ 
       System.out.println("full,can not insert"); 
       return; 
     } 
     array[top++]=value; 
   } 
   public int pop(){ 
     return array[--top]; 
   } 
   public boolean isEmpty(){ 
     if(top == 0){ 
       return true; 
     } 
     return false; 
   } 
   public boolean isFull(){ 
     if(top == max ){ 
       return true; 
     } 
     return false; 
   } 
   public void display(){ 
     while(!isEmpty()){ 
       System.out.println(pop()); 
     } 
   } 
   public static void main(String[] args) { 
     Stack s = new Stack(5); 
     s.push(1); 
     s.push(3); 
     s.push(5); 
     s.push(5); 
     s.push(5); 
     s.display(); 
   } 
 } 

 public String reverse(String in){ 
     String out=""; 
     for (int i = 0; i < in.length(); i++) { 
       char c = in.charAt(i); 
       push(c); 
     } 
     while(!isEmpty()){ 
       out+=pop(); 
     } 
     return out; 
   } 
   public static void main(String[] args) { 
     Scanner s = new Scanner(System.in); 
     String string = s.nextLine(); 
     Stack st = new Stack(string.length()); 
     System.out.println(st.reverse(string));      
   } 

 public static void main(String[] args) { 
   InputStreamReader is = new InputStreamReader(System.in); 
   BufferedReader b = new BufferedReader(is); 
   String string=""; 
   try { 
     string = b.readLine(); 
   } catch (IOException e) { 
     e.printStackTrace(); 
   } 
   Stack st = new Stack(string.length()); 
   System.out.println(st.reverse(string)); 
 } 

 public int charat(char c){ 
   for (int i = 0; i < array.length; i++) { 
     if(c == array[i]) 
       return i; 
   } 
   return array.length; 
 } 
 public void match(String in){ 
   String out=""; 
   for (int i = 0; i < in.length(); i++) { 
     char c = in.charAt(i); 
     if(c == '{' || c == '(' || c == '[' ){ 
       push(c); 
     } 
     if(c == '}' || c == ')' || c == ']'){ 
       char temp = pop(); 
      if(c == '}' && temp != '{'|| c == ')' && temp != '('|| c == ']' && temp != ']'){ 
         System.out.println("can not match in "+i); 
       } 
     } 
   } 
   while(!isEmpty()){ 
     char c = pop(); 
     if(c == '{'){ 
       System.out.println("insert } to match "+charat(c)); 
     } 
     if(c == '[' ){ 
       System.out.println("insert ] to match "+charat(c)); 
     } 
     if(c == '(' ){ 
       System.out.println("insert ) to match "+charat(c)); 
     } 
   } 
 } 
 public static void main(String[] args) { 
   Scanner s = new Scanner(System.in); 
   String string = s.nextLine(); 
   Stack st = new Stack(string.length()); 
   st.match(string); 
 } 
 result： 
 klsjdf(klj{lkjjsdf{) 
 can not match in 19 
 insert } to match 1 
 insert ) to match 0