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
#include<iostream>
#include<string>
#include<stack>

using namespace std;

int main() {

	stack<int> num;
	while (1) {
		string in;
		cin >> in;
		if (in == "+" || in == "-" || in == "*") {
			int a, b;
			b = num.top();
			num.pop();
			a = num.top();
			num.pop();
			if (in == "+")num.push(a + b);
			if (in == "-")num.push(a - b);
			if (in == "*")num.push(a * b);
		}
		else if (cin.eof())break;
		else num.push(stoi(in));
	}

	cout << num.top() << endl;

	return 0;
}
