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 <cstdlib>
#include <stack>
#include <string>

using namespace std;

int main(){
	stack<int> st;
	int a,b;
	string s;

	while(cin>>s)
		if(s[0]=='+'){
			a=st.top();
			st.pop();

			b=st.top();
			st.pop();

			st.push(a+b);
		}else if(s[0]=='-'){
			a=st.top();
			st.pop();

			b=st.top();
			st.pop();

			st.push(b-a);
		}else if(s[0]=='*'){
			a=st.top();
			st.pop();

			b=st.top();
			st.pop();

			st.push(a*b);
		}else{
			st.push(atoi(s.c_str()));
		}

	cout<<st.top()<<endl;
}