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[10000];

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] == '+'){
			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{
			push(atoi(s));
		}
	}

	printf("%d\n", pop());

	return 0;
}
