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 <cstdio>
#include <string>
#include <cstdlib>
#include <stack>

using namespace std;

int main() {

  string c;
  stack<int> st;  
  int a,b;

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