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

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