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 main()
{
	stack<int> s;
	char a;
	int d=0;
	
	while((a=getchar())!=EOF){
		if(isdigit(a)){	
			d=a-'0';
			while((a=getchar())!=' '){
			//	cout<<d<<endl;
				d=d*10+a-'0';
			}
			s.push(d);
		}else{
			int b,c;
			b=s.top();
			s.pop();
			c=s.top();
			s.pop();
			if(a=='+') s.push(c+b);
			if(a=='-') s.push(c-b);
			if(a=='*') s.push(c*b);
			if(a=='/') s.push(c/b);
			getchar();
		}
	}
	
	cout<<s.top()<<endl;
	return 0;
}
