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 <bits/stdc++.h>
using namespace std;

int __p = 0;
int __ST[100];

void s_push(int v){
	__ST[__p++] = v;
}
int s_pop(){
	return __ST[--__p];
}
int main(){
	
	string str;
	
	while(cin >> str){
		if('1'<=str[0] && str[0]<='9'){
			s_push(stoi(str));
		} else {
			int a;
			switch(str[0]){
			case '+':
				s_push(s_pop() + s_pop());
				break;
			case '-':
				a = s_pop();
				s_push(s_pop() - a);
				break;
			case '*':
				s_push(s_pop() * s_pop());
				break;
			}
		}
	}
	cout << s_pop() << endl;
	
	return 0;
}
