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(){
  stack<int> st;
  string s;
  while(cin >> s){
    if(isdigit(s[0])){
      st.push(atoi(s.c_str()));
    }
    else{
      int a = st.top(); st.pop();
      int b = st.top(); st.pop();

      if(s == "+") st.push(b + a);
      if(s == "-") st.push(b - a);
      if(s == "*") st.push(b * a);
    }
  }
  cout << st.top() << endl;
}
