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>
#define	rep(i, n) for (int i = 0; i < (n); ++i)
using	namespace std;
using	ll = long long;
using	P = pair<int, int>;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

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

