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