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<stack>
#include<stdlib.h>

using namespace std;

int a, b;
stack<int> s;

void solution()
{
	a = s.top();
	s.pop();
	b = s.top();
	s.pop();
}


int main()
{
	char str[1000001];

	while(cin>>str)
	{
		switch (str[0])
		{
		case '+':solution(); s.push(a + b); break;
		case '-':solution(); s.push(b - a); break;
		case '*':solution(); s.push(a*b); break;
		case ' ':break;
		default:s.push(atoi(str)); break;
		} 
	}
	cout << s.top() << endl;

return 0;

}
