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>

int main(void){
  std::string str;
  getline(std::cin,str);
  std::istringstream iss(str);
  std::stack<int> stack;
  while(iss >> str){
    if(std::all_of(str.cbegin(),str.cend(),isdigit))stack.push(std::stoi(str));
    else {
      int t=0;
      int a=stack.top();stack.pop();
      int b=stack.top();stack.pop();
      if(str=="+")t=b+a;
      if(str=="-")t=b-a;
      if(str=="*")t=b*a;
      stack.push(t);
    }
  }
  std::cout<<stack.top()<<std::endl;
  return 0;
}

