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 <iostream>
#include <string>
#include <cstdlib>
int main(){
  std::string s;
  int a[100];
  int i=0;
  while (std::cin>>s){
    if (s=="+"){
      i--;
      a[i]+=a[i+1];
    }
    else if (s=="-"){
      i--;
      a[i]-=a[i+1];
    }
    else if (s=="*"){
      i--;
      a[i]*=a[i+1];
    }
    else {
      i++;
      a[i]=atoi(s.c_str());
    }
  }
  std::cout << a[i] << '\n';

}

