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 str;
  stack<int> stk;
  int sum;
  
  while(cin>>str){
    if(str=="+" || str=="-" || str=="*"){
      int x=stk.top();
      stk.pop();
      int y=stk.top();
      stk.pop();
      if(str=="+") sum=y+x;
      if(str=="-") sum=y-x;
      if(str=="*") sum=y*x;
      stk.push(sum);
    }
    else{
      int n=stoi(str);
      stk.push(n);
    }
  }
  
  cout<<stk.top()<<endl;
  return 0;
}

