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 <cstdio>
#include <stdlib.h>
#include <stack>
using namespace std;

int main() {
  stack<int>S;
  int a,b,x;
  string s;

  while (cin>>s){
    if (s=="+"){
      a=S.top();S.pop();
      b=S.top();S.pop();
      S.push(a+b);
    }
    else if (s=="-"){
      a=S.top();S.pop();
      b=S.top();S.pop();
      S.push(b-a);
    }
    else if (s=="*"){
      a=S.top();S.pop();
      b=S.top();S.pop();
      S.push(a*b);
    }
    else{
      S.push(atoi(s.c_str()));
    }

  }
  cout<<S.top()<<endl;
}
