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<int> num;
  string str;

  while(cin >> str){
    if(str == "+" || str == "-" || str == "*"){
      int x = num.top();
      num.pop();
      int y=num.top();
      num.pop();

      if(str=="+"){
	num.push(x+y);
      }
      else if(str=="-"){
	num.push(y-x);
      }
      else if(str=="*"){
	num.push(x*y);
      }
      
    }
    else{
      num.push(atoi(str.c_str()));
    }
  }

  cout << num.top() << endl;

  return 0;
}

