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<stdio.h>
#include<stdlib.h>
#include<string.h>
int top,s[1000];
void push(int x)
{
	s[++top]=x;
}
int pop()
{
	top--;
	return s[top+1];
}
int main()
{
	int a,b,result;
	top=0;
	char s[100];
	while(scanf("%s",s)!=EOF)
	{
		if(s[0]=='+')
		{
			a=pop();
			b=pop();
			push(a+b);
		}
		else if(s[0]=='-')
		{
			b=pop();
			a=pop();
			push(a-b);
		}
		else if(s[0]=='*')
		{
			a=pop();
			b=pop();
			push(a*b);
		}
		else
		{
			result=atoi(s);
			push(result);
		}
	}
	printf("%d\n",pop());
	return 0;
}
