import java.io.*;
import java.lang.*;
class stack {
    private final int STACKSIZE = 50;
    private int top;
    private char items[];
    public stack() {
        top = -1;
        items = new char[STACKSIZE];
    }
    public void push(char a) {
        if (top == STACKSIZE - 1) {
            System.out.println("overflow");
            return;
        } else
            top++;
        items[top] = a;
    }
    public boolean isEmpty() {
        if (top == -1)
            return true;
        else
            return false;
    }
    public char pop() {
        if (top == -1) {
            System.out.print("empty, cannot pop");
            return ' ';
        }
        return (items[top--]);
    }
    public char peek() {
        if (top == -1) {
            System.out.println("empty, can not peek");
            return ' ';
        }
        return (items[top]);
    }
    public void display() {
        for (int i = top; i >= 0; i--)
            System.out.println(items[i]);
    }
}
class Infix2Postfix {
    private boolean isOpenBracket(char m) {
        if (m == '(')
            return true;
        else
            return false;
    }
    private boolean isOperator(char m) {
        if (m == '+' || m == '-' || m == '/' || m == '*')
            return true;
        else
            return false;
    }
    private boolean isOperand(char m) {
        if ((m >= '0' && m <= '9') || (m >= 'a' && m <= 'z') || (m >= 'A' && m <= 'Z'))
            return true;
        else
            return false;
    }
    private int priority(char ch) {
        int priority;
        priority = 0;;
        switch (ch) {
            case '+':
                priority = 3;
                break;
            case '-':
                priority = 2;
                break;
            case '*':
                priority = 5;
                break;
            case '/':
                priority = 4;
                break;
            case '%':
                priority = 1;
                break;
        }
        return priority;
    }
    public void convert(String str) {
        char ch;
        stack s = new stack();
        int i, j;
        j = 0;
        char postfix[] = new char[str.length()];
        for (i = 0; i < str.length(); i++) {
            ch = str.charAt(i);
            if (isOpenBracket(ch))
                s.push(ch);
            else if (isOperand(ch))
                postfix[j++] = ch;
            else if (isOperator(ch))
                if (s.isEmpty())
                    s.push(ch);
                else {
                    if (priority(ch) >= priority(s.peek()))
                        s.push(ch);
                    else {
                        while (priority(ch) < priority(s.peek()))
                            postfix[j++] = s.pop();
                        s.push(ch);
                    }
                }
            else if (!isOpenBracket(ch)) {
                while (!isOpenBracket(s.peek()))
                    postfix[j++] = s.pop();
                if (isOpenBracket(s.peek()))
                    s.pop();
            }
        }
        while (!s.isEmpty()) {
            postfix[j++] = s.pop();
        }
        for (i = 0; i < str.length(); i++)
            System.out.print(postfix[i]);
    }
}
public class Infixtopostfix {
    public static void main(String[] args) throws IOException {
        String str;
        Infix2Postfix in2post = new Infix2Postfix();
        BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));
        System.out.println();
        System.out.println("Enter an expression in infix notation");
        str = obj.readLine();
        System.out.println("Postfix notation is");
        in2post.convert(str);
    }
}

/* Output
Enter an expression in infix notation
(A+B)*(C+D)

Postfix notation is
AB+CD+*

Enter an expression in infix notation
(A/B)*(C/D)
Postfix notation is
AB/CD/*

*/