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 <bits/stdc++.h>

using namespace std;

int main() {
	stack<int> s;
	while (int c = cin.peek()) {
		if (c == cin.eof()) break;
		if (c <= 32) break;

		if (c >= '0' && c <= '9') {
			int x;
			cin >> x;
			s.push(x);
		} else {
			char op;
			cin >> op;

			int y = s.top();
			s.pop();
			int x = s.top();
			s.pop();

			if (op == '+') {
				s.push(x + y);
			} else if (op == '-') {
				s.push(x - y);
			} else {
				s.push(x * y);
			}
		}

		cin.ignore();
	}

	cout << s.top() << endl;
}
