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 <string>

using namespace std;

int stack[100];
int tail = 0;

void push(int v) {
	stack[tail++] = v;
}

int pop() {
	tail--;
	return stack[tail];
}

int main() {
	int x, y;
	string s;
	while (cin >> s) {
		if (s == "+" || s == "-" || s == "*") {
			y = pop();
			x = pop();
			if (s == "+")
				push(x + y);
			if (s == "-")
				push(x - y);
			if (s == "*")
				push(x * y);
		}
		else {
			push(stoi(s));
		}
		
	}
	cout << pop() << endl;

	return 0;
}
