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

int main() {
	stack<int> S;
	int a, b, x;
	string s;

	while (cin >> s) {
		if (s[0] == '+') {
			a = S.top(); S.pop();
			b = S.top(); S.pop();
			S.push(a + b);
		}
		else if (s[0] == '-') {
			b = S.top(); S.pop();
			a = S.top(); S.pop();
			S.push(a - b);
		}
		else if (s[0] == '*')  {
			a = S.top(); S.pop();
			b = S.top(); S.pop();
			S.push(a * b);
		}
		else {
			S.push(atoi(s.c_str()));
		}
	}

	cout << S.top() << endl;

	return 0;
}