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>

using namespace std;

int top = 0, S[200];


void push(int elem) {
	S[top] = elem; 
	++top;
	return;
}

int pop() {
	--top;
	return S[top];
}

int main() {
	int a, b;
	char C[200];
	while (cin >> C) {
		if (C[0] == '+') {
			a = pop();
			b = pop();
			push(a + b);
		}

		else if (C[0] == '-') {
			b = pop();
			a = pop();
			push(a - b);
		}

		else if (C[0] == '*') {
			a = pop();
			b = pop();
			push(a*b);
		}
		else {
			push(atoi(C));
		}
	}
	cout << pop() << endl;
	return 0;
}
	