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>
using namespace std;

int main(){
	stack<int> a;
	int x,y;
	string s;
	while(cin>>s){
		if(s[0] == '+'){
			x = a.top();a.pop() ;
			y = a.top(); a.pop() ;
			a.push(x+y);  
		}
		else if(s[0] == '-'){
			x = a.top();a.pop() ;
			y = a.top(); a.pop() ;
			a.push(y-x);
		}
		else if(s[0] == '*'){
			x = a.top();a.pop() ;
			y = a.top(); a.pop() ;
			a.push(x*y);  
		}
		else{
			a.push(atoi(s.c_str()));
		}
	}
	cout<<a.top()<<endl ;
	return 0;
}
