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 <bits/stdc++.h>
using namespace std;
int main(){
	stack<int> s;
	string tmp;
	while( cin>>tmp ){
		if(tmp=="+"){
			int b = s.top();
			s.pop();
			int a = s.top();
			s.pop();
			s.push(a+b);
		} else if(tmp=="-"){
			int b = s.top();
			s.pop();
			int a = s.top();
			s.pop();
			s.push(a-b);
		} else if(tmp=="*"){
			int b = s.top();
			s.pop();
			int a = s.top();
			s.pop();
			s.push(a*b);
		} else {
			int a = stoi(tmp);
			s.push(a);
		}
	}
	int result = s.top();
	cout<<result<<endl;
	return 0;
}