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 <stack>
using namespace std;
int main(){
  int a,b;
  string ch;
  stack<int> S;
  while(cin>>ch){
    if(ch[0]=='+'){
      a=S.top();S.pop();
      b=S.top();S.pop();
      S.push(a+b);
    } else if(ch[0]=='-'){
      b=S.top();S.pop();
      a=S.top();S.pop();
      S.push(a-b);
    } else if(ch[0]=='*'){
      a=S.top();S.pop();
      b=S.top();S.pop();
      S.push(a*b);
    } else {
      S.push(atoi(ch.c_str()));
    }
  }
  cout<<S.top()<<endl;
  return 0;
}