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 a;
	int n, m;
	stack<int> s;
	while (cin>>a)
	{
		if (a == "+")
		{
			m = s.top(); s.pop();
			n = s.top(); s.pop();
			s.push(n + m);
		}
		else if (a == "-")
		{
			m = s.top(); s.pop();
			n = s.top(); s.pop();
			s.push(n - m);
		}
		else if (a == "*")
		{
			m = s.top(); s.pop();
			n = s.top(); s.pop();
			s.push(n*m);
		}
		else
		{
			s.push(stoi(a));
		}
	}
	cout << s.top() << endl;
    return 0;
}