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>
#include<cstdlib>

using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int s[100];
	int *sp=s;
	string str;
	while(cin>>str) {
		if(str=="+") {
			--sp;
			*(sp-1)+=*sp;
		} else if(str=="-") {
			--sp;
			*(sp-1)-=*sp;
		} else if(str=="*") {
			--sp;
			*(sp-1)*=*sp;
		} else {
			*sp++=atoi(str.c_str());
		}
	}
	cout<<*--sp<<'\n';
	return 0;
}

