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<string>
#include<cstdlib>
#include<iostream>
using namespace std;

int S[1000];
int top = 0;

void push(int x)
{
	S[top++] = x;
}

int pop()
{
	top--;
	return S[top];
}

int main()
{
	int a, b;
	char s[100];
	while(cin>>s)
	{
		if (s[0] == '+')
		{
			a = pop();
			b = pop();
			push(a + b);
		}
		else if (s[0] == '-')
		{
			a = pop();
			b = pop();
			push(b - a);
		}
		else if (s[0] == '*')
		{
			a = pop();
			b = pop();
			push(a * b);
		}
		else
			push(atoi(s));
	}
	cout << S[top - 1] << endl;
}
