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 <stack>
#include <string>
#include <cstdlib>
#include <iostream>

using namespace std;

int main(){
	stack<int> D;
	string S;
	while (cin >> S){
		if (S == "+" || S == "-" || S == "*") {
			int B = D.top();
			D.pop();
			int A = D.top();
			D.pop();
			if (S == "+")D.push(A + B);
			if (S == "-")D.push(A - B);
			if (S == "*")D.push(A * B);
		}
		else D.push(atoi(S.c_str()));
	}
	cout << D.top() << endl;
}
