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.*;
import java.io.*;
class Main{
	public static void main(String[]args){
		Scanner in=new Scanner(System.in);
		PrintWriter out=new PrintWriter(System.out, true);
		String str[]=in.nextLine().split(" ");
		Stack<Integer> st=new Stack<>();
		for(int i=0;i<str.length;i++){
			try{
				int a=Integer.parseInt(str[i]);
				st.push(a);
			}catch(Exception e){
				if(str[i].equals("+")){
					int a=st.pop();
					int b=st.pop();
					st.push(a+b);
				}else if(str[i].equals("-")){

					int a=st.pop();
					int b=st.pop();
					st.push(b-a);
				}else{
					int a=st.pop();
					int b=st.pop();
					st.push(a*b);
				}
			}
		}
		out.println(st.pop());
	}

}
