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 S[1000], top;
void push(int i){
	S[top] = i;
	top++;
}
int pop() {
	int i = S[top-1];
	top--;
	return i;
}
int main() {
	int i, j;
	char c[100];
	while (cin >> c) {
		if (c[0] == '+') {
			i = pop();
			j = pop();
			push(i + j);
		}
		else if (c[0] == '-') {
			i = pop();
			j = pop();
			push(j - i);
		}
		else if (c[0] == '*') {
			i = pop();
			j = pop();
			push(i*j);
		}
		else push(atoi(c));
	}
	cout << pop() << endl;
	return 0;
}