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<cstdio>
#include<algorithm>
#include<stack>
#include<cstdlib>
using namespace std;
stack <int> s1;

int main() {
	char c[20];
	while (cin >> c) {

		if (c[0] != '+' && c[0] != '-' && c[0] != '*') s1.push(atoi(c));
		else {
			int x, y;
			x = s1.top();
			s1.pop();
			y = s1.top();
			s1.pop();
			if (c[0] == '+') s1.push(x + y);
			else if (c[0] == '-') s1.push(y - x);
			else if (c[0] == '*') s1.push(y * x);
		}		
		char a;
		cin.get(a);
		if (a == '\n') break;
	}
	cout << s1.top() << endl;
}

