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 <sstream>
#include <cstdlib>
#include <stack>

using namespace std;

int main() {

  string op;
  stack<int> st;  
  int sec,fir;

  while(cin >> op){
    if(op=="+"||op=="-"||op=="*"){
      fir = st.top();
      st.pop();
      sec = st.top();
      st.pop();
      if(op=="+") st.push(fir+sec);
      if(op=="-") st.push(sec-fir);
      if(op=="*") st.push(fir*sec);
    }
    else st.push(atoi(op.c_str()));
  }
  cout << st.top() << endl;
  
}
