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>

int top = 0;
int S[105];


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

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

int main()
{
	char s[10];
	int a, b,c;

	while (scanf("%s",s,10)!=EOF)
	{
		if (s[0] == '+')
		{
			b = pop();
			a = pop();
			c = a + b;
			push(c);
		}
		else if (s[0] == '-')
		{
			b = pop();
			a = pop();
			c = a - b;
			push(c);
		}
		else if (s[0] == '*')
		{
			b = pop();
			a = pop();
			c = a * b;
			push(c);
		}
		else
			push(atoi(s));
	}
	printf("%d\n",pop());
	return 0;
}
