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;
	top = 0;
	char s[100];
	while(scanf("%s", s) != EOF)
	{
		if(s[0] == '+')
		{
			b = pop();
			a = pop();
			push(a + b);
		}
		else if(s[0] == '-')
		{
			b = pop();
			a = pop();
			push(a - b);
		}
		else if(s[0] == '*')
		{
			b = pop();
			a = pop();
			push(a * b);
		}
		else
			push(atoi(s));
	 } 
	 printf("%d\n", pop());
	 return 0;
}

