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 <bits/stdc++.h>
using namespace std;
int main(){
  int x;
  stack<int> a;
  string b;
  while(cin >> b){
    if (b =="+"||b =="-"||b=="*"){
        int x = a.top();
        a.pop();
        int y = a.top();
        a.pop();
        if(b == "+") a.push(x+y);
        if(b == "-") a.push(y-x);
        if(b == "*") a.push(x*y);
    } 
    else {
      x = stoi(b);
      a.push(x);
    }
  }
  cout << a.top() << endl;
  return 0;
}
