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 <cstdlib>

int main(){
  int x[100]={0},i=0,ans=0;
  char s[100];

  while(std::cin>>s){
    if(s[0]=='+'){
      ans=x[i-2]+x[i-1];
      x[i-2]=ans;
      x[i-1]=0;
      if(i!=1) i--;
    }else if(s[0]=='-'){
      ans=x[i-2]-x[i-1];
      x[i-2]=ans;
      x[i-1]=0;
      if(i!=1) i--;
    }else if(s[0]=='*'){
      ans=x[i-2]*x[i-1];
      x[i-2]=ans;
      x[i-1]=0;
      if(i!=1) i--;
    }else{
      x[i]=atoi(s);
      i++;
    }
  }

  std::cout<<ans<<"\n";

  return 0;
}
