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<long long>st;
	string c;
	while(cin>>c){
		if(c=="+"){
			long long a=st.top();
			st.pop();
			long long b=st.top();
			st.pop();
			st.push(a+b);
		}
		else if(c=="-"){
			long long a=st.top();
			st.pop();
			long long b=st.top();
			st.pop();
			st.push(b-a);
		}
		else if(c=="*"){
			long long a=st.top();
			st.pop();
			long long b=st.top();
			st.pop();
			st.push(a*b);
		}
		else{
			st.push(stoi(c));
		}
	}
	cout<<st.top()<<endl;
	return 0;
}