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() {
  string s;
  stack<long> S;
  while (cin >> s) {
    if (s == "+") {
      int x1 = S.top(); S.pop();
      int x2 = S.top(); S.pop();
      S.push(x1 + x2);
    } else if (s == "-") {
      int x1 = S.top(); S.pop();
      int x2 = S.top(); S.pop();
      S.push(x2 - x1);
    } else if (s == "*") {
      int x1 = S.top(); S.pop();
      int x2 = S.top(); S.pop();
      S.push(x1 * x2);
    } else {
      S.push(stol(s));
    }
  }
  cout << S.top() << endl;
}
