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;
	char n;
	string s;
	int a, b;
	while (cin >> s) {
		if (s[0] == '+' || s[0]=='-'||s[0]=='*') {
			a = S.top();
			S.pop();
			b = S.top();
			S.pop();
			if (s[0] == '+') {
				S.push(a + b);
			}
			else if (s[0] == '-') {
				S.push(b - a);
			}
			else if (s[0] == '*') {
				S.push(a * b);
			}
		}
		else {
			S.push(atoi(s.c_str()));
		}
	}
	cout << S.top() << endl;
}
