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<stdlib.h>
using namespace std;

int top, S[1000];

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

int pop(void) {
	top--;
	return S[top+1];
}

int main(void) {
	int a, b;
	top = 0;
	char s[10];

	while (cin >> s) {
		if (s[0] == '+') {
			a = pop();
			b = pop();
			push(a + b);
		}
		else if (s[0] == '-') {
			a = pop();
			b = pop();
			push(b - a);
		}
		else if (s[0] == '*') {
			a = pop();
			b = pop();
			push(a * b);
		}
		else {
			push(atoi(s));
		}
	}
	
	cout << pop() << endl;

	return 0;
}