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>
using namespace std;

int main(){
	stack<int> st;
	string n;
	int x,y;
	while(cin >> n){
		if(n == "+"){
			x = st.top();
			st.pop();
			y = st.top();
			st.pop();
			st.push(y+x);
		}else if(n == "-"){
			x = st.top();
			st.pop();
			y = st.top();
			st.pop();
			st.push(y-x);
		}else if(n == "*"){
			x = st.top();
			st.pop();
			y = st.top();
			st.pop();
			st.push(y*x);
		}else{
			st.push(stoi(n));
		}
	}
	cout << st.top() << endl;
	return 0;
}	