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;
typedef long long ll;
#define INF (1e9)

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

  while(cin >> str) {
    if(str == "+" || str == "-" || str == "*") {
      a = s.top();
      s.pop();
      b = s.top();
      s.pop();
    }

    if(str == "+") {
      s.push(a + b);
    } else if(str == "-") {
      s.push(-a + b);
    } else if(str == "*") {
      s.push(a * b);
    } else {
      s.push(stoi(str));
    }
  }

  cout << s.top() << endl;

  return 0;
}
