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()
{
	stack<int> S;
	int a,b;
	string t;
	while (cin >> t)
	{
		if (t[0] == '+')
		{
			a = S.top(); S.pop();
			b = S.top(); S.pop();
			S.push(a+b);
		}
		else if (t[0] == '-')
		{
			a = S.top(); S.pop();
			b = S.top(); S.pop();
			S.push(b-a);	
		}
		else if (t[0] == '*')
		{
			a = S.top(); S.pop();
			b = S.top(); S.pop();
			S.push(a*b);
		}
		else
			S.push(stoi(t));
	}
	cout << S.top() << endl;
}

