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 <stack>
#include <string>

using namespace std;

int main()
{
	stack<long> s;
	string i;

	while (cin >> i) {
		if (i == "+") {
			int a, b;
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a + b);
		} else if (i == "-") {
			int a, b;
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a - b);
		} else if (i == "*") {
			int a, b;
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a * b);
		} else {
			s.push(stoi(i));
		}
	}
	cout << s.top() << endl;
}