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 <bits/stdc++.h>


using namespace std;


int main() {
	int tmp1, tmp2;
	stack<int> s;
	string a;
	
	while(cin >> a) {
		if (a == "+" || a == "-" || a == "*") {
			tmp2 = s.top();
			s.pop();
			tmp1 = s.top();
			s.pop();
			if (a == "+") { s.push(tmp1 + tmp2); }
			if (a == "-") { s.push(tmp1 - tmp2); }
			if (a == "*") { s.push(tmp1 * tmp2); }
		}
		else {
			s.push(atoi(a.c_str()));
		}
	}
	cout << s.top()<<endl;
	
	return 0;
}

