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(){
	string va[200];
	int i=0;
	stack <int> st;
	while(cin >> va[i]){
		if(va[i]!="+" && va[i]!="-" && va[i]!="*" ){
			st.push(atoi(va[i].c_str()));
		}
		else{
			int b=st.top();
			st.pop();
			int a=st.top();
			st.pop();
			int ans;
			if(va[i]=="+")
				ans=a+b;
			else if(va[i]=="-")
				ans=a-b;
			else
				ans=a*b;
			st.push(ans);
		}
		i++;
	}
	cout << st.top() << endl;
	return 0;
}