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 <stack>
#include <cctype>
#include <algorithm>
using namespace std;
int main(void){
  stack<int> s;
  int a,b;
  string n;
  while(cin>>n){
    if(isdigit(n[0]))
      s.push(atoi(n.c_str()));
    else{
      a=s.top();
      s.pop();
      b=s.top();
      s.pop();
      if(n[0]=='+')
	b+=a;
      else if(n[0]=='-')
	b-=a;
      else if(n[0]=='*')
	b*=a;
      s.push(b);
    }
  }
  cout<<s.top()<<endl;
  return 0;
}