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 <stack>
#include <cstdlib>
using namespace std;

stack <int> s1; 



int main(){
	int a,b;
	string s;
	
	while(cin>>s){
		if(s=="+"){
			a=s1.top();
			s1.pop();
			b=s1.top();
			s1.pop();
			s1.push(b+a);
		}
		else if(s=="-"){
			a=s1.top();
			s1.pop();
			b=s1.top();
			s1.pop();
			s1.push(b-a);
		}
		else if(s=="*"){
			a=s1.top();
			s1.pop();
			b=s1.top();
			s1.pop();
			s1.push(b*a);
		} 
		else{
			s1.push(atoi(s.c_str()));
		}
	}
	cout<<s1.top()<<endl;
} 