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

int main(){
  stack<int> S;
  int a,b;
  string s;

  while(cin >> s){
    if(s[0] == '+'){
      b = S.top(); S.pop();
      a = 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] == '*'){
      b = S.top(); S.pop();
      a = S.top(); S.pop();
      S.push(a * b);
    } else S.push(atoi(s.c_str()));
  }
  cout << S.top() << endl;
}
