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> st;
	string str;
	while(cin >> str){
		char c = str[0];
		if(isdigit(c)){
			st.push(stoi(str));
		}else{
			int y = st.top();st.pop();
			int x = st.top();st.pop();
			if(c == '+'){
				st.push(x+y);
			}else if(c == '-'){
				st.push(x-y);
			}else if(c == '*'){
				st.push(x*y);
			}
		}
		cin.ignore();
	}
	cout << st.top() << endl;
	
	return 0;
}