Notes

Template in C

Constraints

2 ≤ the number of operands in the expression ≤ 100
1 ≤ the number of operators in the expression ≤ 99
-1 × 109 ≤ values in the stack ≤ 109

Input

An expression is given in a line. Two consequtive symbols (operand or operator) are separated by a space character.

You can assume that +, - and * are given as the operator and an operand is a positive integer less than 106

Output

Print the computational result in a line.

Examples

Input

1 2 +


Output

3


Input

1 2 + 3 4 - *


Output

-3
import java.util.Scanner;
import java.util.Stack;

class Main{
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);

    Stack<Integer> main = new Stack<>();

    while(scan.hasNext()) {
      String inputString = scan.next();
      char[] input = inputString.toCharArray();
      if(input[0]>='0'&&input[0]<='9') {
        main.push(Integer.parseInt(inputString));
      }else {
        if(input[0]=='+') {
          main.push(main.pop()+main.pop());
        }else if(input[0]=='-') {
          main.push(-main.pop()+main.pop());
        }else {
          main.push(main.pop()*main.pop());
        }
      }
    }
    System.out.println(main.pop());
  }
}