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<string>
#include<stack>
#include<cstdlib>

int main(){
	std::stack<int>s;
	std::string str;
	while(std::cin>>str){
		if(str=="+"){
			int a=s.top();
			s.pop();
			int b=s.top();
			s.pop();
			s.push(a+b);
		}
		else if(str=="-"){
			int a=s.top();
			s.pop();
			int b=s.top();
			s.pop();
			s.push(b-a);
		}
		else if(str=="*"){
			int a=s.top();
			s.pop();
			int b=s.top();
			s.pop();
			s.push(a*b);
		}
		else s.push(atoi(str.c_str()));
	}
	std::cout<<s.top()<<std::endl;
	return 0;
}