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<iostream>
#include<stdio.h>
#include<cstdlib>

int top,S[1000];

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

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

int main(){
	int a,b;
	top = 0;
	char s;
	
	while (scanf("%s", &s) != EOF) {
		if (s == '+') {
			a = push();
			b = push();
			pop(a + b);
		} else if (s == '-') {
			b = push();
			a = push();
			pop(a - b);
		} else if (s == '*') {
			a = push();
			b = push();
			pop(a * b);
		} else {
			pop(std::atoi(&s));
		}
	}
	
	std::cout << push() << std::endl;
	
	return 0;
}

