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<stack>
#include<cstdlib>
using namespace std;


int main(){
	stack<int> s;
	int a,b;
	string st;
	while(cin >> st){
		if(st[0]=='+'){
			a=s.top();s.pop();
			b=s.top();s.pop();
			s.push(a+b);
		}
		else if(st[0]=='-'){
			b=s.top();s.pop();
			a=s.top();s.pop();
			s.push(a-b);
		}
		else if(st[0]=='*'){
			a=s.top();s.pop();
			b=s.top();s.pop();
			s.push(a*b);
		}
		else{
			s.push(atoi(st.c_str()));
		}
	}
		printf("%d\n",s.top());
	
	return 0;
}
