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() {
	int i, j, a, b;
	string c;
	stack<int> s;
	while (cin >> c) {
		if (c[0] == '+') {
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a + b);
		} else if (c[0] == '-') {
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a - b);
		} else if (c[0] == '*') {
			b = s.top();
			s.pop();
			a = s.top();
			s.pop();
			s.push(a * b);
		} else {
			s.push(atoi(c.c_str()));
		}
	}
	cout << s.top() << endl;
	return 0;
}