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<cstdio>
#include<cstdlib>
using namespace std;

int top,S[1000];

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

int pop()
{
	top--;
	return S[top+1];
}

int main()
{
	char s;int a,b;
	while(scanf("%s",&s)!=EOF)
	{
		if(s=='+')
		{
			a=pop(),b=pop();
			push(b+a);
		}
		else if(s=='-')
		{
			a=pop(),b=pop();
			push(b-a);
		}
		else if(s=='*')
		{
			a=pop(),b=pop();
			push(b*a);
		}
		else
		{
			push(atoi(&s));
		}
	}
	printf("%d\n",pop());
	return 0;
}