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>
#include <vector>
#include <stack>
using namespace std;

int main(){
  stack<int> S;
  int a,b,x;
  string s;
  
  while(cin>>s){
  	if(s[0]=='+'){
    	a=S.top();S.pop();
      	b=S.top();S.pop();
      	S.push(a+b);
    }else if(s[0]=='-'){
    	b=S.top();S.pop();
      	a=S.top();S.pop();
      	S.push(a-b);
    }else if(s[0]=='*'){
    	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;
}
