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

int main(void){
	stack<int> st;
	string ch;
	while(cin >> ch){
		if(isdigit(ch[0])){
			st.push(atoi(ch.c_str()));
		}
		else{
			int a = st.top();
			st.pop();
			int b = st.top();
			st.pop();
			if(ch == "+") st.push(b + a);
			if(ch == "-") st.push(b - a);
			if(ch == "*") st.push(b * a);
		}
	}
	cout << st.top() << endl;
	return 0;
}
