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.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String[] ary =  br.readLine().split(" ");
		int[] stack = new int[ary.length];
		int stackCount = -1;
		for(int i = 0 ; i < ary.length ; i++){
			if(ary[i].equals("+")){
				stack[stackCount - 1] = stack[stackCount - 1] + stack[stackCount];
				stackCount--;
			}else if(ary[i].equals("-")){
				stack[stackCount - 1] = stack[stackCount - 1] - stack[stackCount];
				stackCount--;
			}else if(ary[i].equals("*")){
				stack[stackCount - 1] = stack[stackCount - 1] * stack[stackCount];
				stackCount--;
			}else{
				stack[++stackCount] = Integer.parseInt(ary[i]);
			}
		}

		System.out.println(stack[stackCount]);
	}

}