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<string>st;
  string s;
  while(cin>>s){
     if(s == "+" || s == "-" || s == "*"){
            int b = stoi(st.top()); st.pop();
            int a = stoi(st.top()); st.pop();
            int number;
            if(s == "+") number = a + b;
            if(s == "-") number = a - b;
            if(s == "*") number = a * b;
            st.push(to_string(number));
        }else{
            st.push(s);
        }
    }
    cout << st.top() << endl;
}
