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<algorithm>
using namespace std;

int top, cpp[1000];
void push(int s)
{
	cpp[++top] = s;
}
int pop()
{
	
	return cpp[top--];
}

int main()
{
	int n, i;
	char c[3];
	top = 0;
	while (cin >> c)
	{
		if (c[0] == '+')
		{
			n = pop();
			i = pop();
			push(n + i);
		}
		else if (c[0] == '-')
		{
			n = pop();
			i = pop();
			push(i - n);
		}
		else if (c[0] == '*')
		{
			n = pop();
			i = pop();
			push(n * i);
		}
		else push(atoi(c));
	}
	cout << pop() << endl;
	return 0;
}
