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>
using namespace std;
int main(){
  int S[100],top=0;
  string s;
  while(cin>>s){
    if(s=="+")
      {S[top-1]+=S[top];--top;}
    else if(s=="-")
      {S[top-1]-=S[top];--top;}
    else if(s=="*")
      {S[top-1]*=S[top];--top;}
    else
      {S[++top]=atoi(s.c_str());}
  }
  cout<<S[top]<<endl;
  return 0;
}