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() {
	string s;
	stack<int> st;

	while (cin >> s) {
		if (s == "+" || s == "-" || s == "*") {
			int n1, n2;
			n1 = st.top();
			st.pop();
			n2 = st.top();
			st.pop();
			if (s == "+") {
				st.push(n1 + n2);
			}
			else if (s == "-") {
				st.push(n2 - n1);
			}
			else if (s == "*") {
				st.push(n1 * n2);
			}
		}
		else {
			st.push(stoi(s));
		}
	}
	cout << st.top() << endl;

	return 0;
}