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 r = new BufferedReader(new InputStreamReader(System.in));
        String line = r.readLine();
        int opIndex = 0;
        int[] ops = new int[100];
        for (String elem : line.split(" ")) {
            if (elem.equals("+")) {
                ops[opIndex - 2] += ops[opIndex - 1];
                opIndex--;
            } else if (elem.equals("-")) {
                ops[opIndex - 2] -= ops[opIndex - 1];
                opIndex--;
            } else if (elem.equals("*")) {
                ops[opIndex - 2] *= ops[opIndex - 1];
                opIndex--;
            } else {
                ops[opIndex++] = Integer.parseInt(elem);
            }
        }
        System.out.println(ops[0]);
    }
}