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;
public class Main {
  static int top = 0;
  static int[] number = new int[200];

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String s = sc.nextLine();
    String[] str = s.split(" ",0);
    for(int i = 0; i<str.length; i++){
      if(str[i].equals("+")) {
        int a = pop();
        int b = pop();
        push(b+a);
        continue;
      }
      if(str[i].equals("-")) {
        int a = pop();
        int b = pop();
        push(b-a);
        continue;
      }
      if(str[i].equals("*")) {
        int a = pop();
        int b = pop();
        push(b*a);
        continue;
      }
      push(Integer.parseInt(str[i]));
    }
    System.out.println(pop());
  }
  public static int pop() {
    top--;
    return number[top+1];
  }
  public static void push(int i) {
    top++;
    number[top] = i;
  }
}